This document describes all commands currently supported by QMP.
Most of the time their usage is exactly the same as in the user Monitor, this means that any other document which also describe commands (the manpage, QEMU’s manual, etc) can and should be consulted.
QMP has two types of commands: regular and query commands. Regular commands usually change the Virtual Machine’s state someway, while query commands just return information. The sections below are divided accordingly.
It’s important to observe that all communication examples are formatted in a reader-friendly way, so that they’re easier to understand. However, in real protocol usage, they’re emitted as a single line.
Also, the following notation is used to denote data flow:
Example:
-> data issued by the Client
<- Server data response
Please, refer to the QMP specification (docs/interop/qmp-spec.txt) for detailed information on the Server command and response formats.
The current QMP command set (described in this file) may be useful for a number of use cases, however it’s limited and several commands have bad defined semantics, specially with regard to command completion.
These problems are going to be solved incrementally in the next QEMU releases and we’re going to establish a deprecation policy for badly defined commands.
If you’re planning to adopt QMP, please observe the following:
QEMU error classes
Values:
GenericError
this is used for errors that don’t require a specific error class. This should be the default case for most errors
CommandNotFound
the requested command has not been found
DeviceNotActive
a device has failed to be become active
DeviceNotFound
the requested device has not been found
KVMMissingCap
the requested operation can’t be fulfilled because a required KVM capability is missing
Since: 1.2
An enumeration of the I/O operation types
Values:
read
read operation
write
write operation
Since: 2.1
An enumeration of three options: on, off, and auto
Values:
auto
QEMU selects the value between on and off
on
Enabled
off
Disabled
Since: 2.2
An enumeration of three values: on, off, and split
Values:
on
Enabled
off
Disabled
split
Mixed
Since: 2.6
A fat type wrapping ’str’, to be embedded in lists.
Members:
str: string
Not documented
Since: 1.2
This is a string value or the explicit lack of a string (null pointer in C). Intended for cases when ’optional absent’ already has a different meaning.
Members:
s: string
the string value
n: null
no string value
Since: 2.10
An enumeration of options for specifying a PCI BAR
Values:
off
The specified feature is disabled
auto
The PCI BAR for the feature is automatically selected
bar0
PCI BAR0 is used for the feature
bar1
PCI BAR1 is used for the feature
bar2
PCI BAR2 is used for the feature
bar3
PCI BAR3 is used for the feature
bar4
PCI BAR4 is used for the feature
bar5
PCI BAR5 is used for the feature
Since: 2.12
An enumeration of PCIe link speeds in units of GT/s
Values:
2_5
2.5GT/s
5
5.0GT/s
8
8.0GT/s
16
16.0GT/s
Since: 4.0
An enumeration of PCIe link width
Values:
1
x1
2
x2
4
x4
8
x8
12
x12
16
x16
32
x32
Since: 4.0
The network address family
Values:
ipv4
IPV4 family
ipv6
IPV6 family
unix
unix socket
vsock
vsock family (since 2.8)
unknown
otherwise
Since: 2.1
Members:
host: string
host part of the address
port: string
port part of the address
Captures a socket address or address range in the Internet namespace.
Members:
numeric: boolean
(optional)true if the host/port are guaranteed to be numeric, false if name resolution should be attempted. Defaults to false. (Since 2.9)
to: int
(optional)If present, this is range of possible addresses, with port
between port
and to
.
ipv4: boolean
(optional)whether to accept IPv4 addresses, default try both IPv4 and IPv6
ipv6: boolean
(optional)whether to accept IPv6 addresses, default try both IPv4 and IPv6
keep-alive: boolean
(optional)enable keep-alive when connecting to this socket. Not supported for passive sockets. (Since 4.2)
InetSocketAddressBase
Since: 1.3
Captures a socket address in the local ("Unix socket") namespace.
Members:
path: string
filesystem path to use
tight: boolean
(optional)pass a socket address length confined to the minimum length of the abstract string, rather than the full sockaddr_un record length (only matters for abstract sockets, default true). (Since 5.1)
abstract: boolean
(optional)whether this is an abstract address, default false. (Since 5.1)
Since: 1.3
Captures a socket address in the vsock namespace.
Members:
cid: string
unique host identifier
port: string
port
Note: string types are used to allow for possible future hostname or service resolution support.
Since: 2.8
Captures the address of a socket, which could also be a named file descriptor
Members:
type
One of "inet", "unix", "vsock", "fd"
data: InetSocketAddress
when type
is "inet"data: UnixSocketAddress
when type
is "unix"data: VsockSocketAddress
when type
is "vsock"data: String
when type
is "fd"Note: This type is deprecated in favor of SocketAddress. The difference between SocketAddressLegacy and SocketAddress is that the latter is a flat union rather than a simple union. Flat is nicer because it avoids nesting on the wire, i.e. that form has fewer {}.
Since: 1.3
Available SocketAddress types
Values:
inet
Internet address
unix
Unix domain socket
vsock
VMCI address
fd
decimal is for file descriptor number, otherwise a file descriptor name. Named file descriptors are permitted in monitor commands, in combination with the ’getfd’ command. Decimal file descriptors are permitted at startup or other contexts where no monitor context is active.
Since: 2.9
Captures the address of a socket, which could also be a named file descriptor
Members:
type: SocketAddressType
Transport type
InetSocketAddress
when type
is "inet"UnixSocketAddress
when type
is "unix"VsockSocketAddress
when type
is "vsock"String
when type
is "fd"Since: 2.9
An enumeration of VM run states.
Values:
debug
QEMU is running on a debugger
finish-migrate
guest is paused to finish the migration process
inmigrate
guest is paused waiting for an incoming migration. Note that this state does not tell whether the machine will start at the end of the migration. This depends on the command-line -S option and any invocation of ’stop’ or ’cont’ that has happened since QEMU was started.
internal-error
An internal error that prevents further guest execution has occurred
io-error
the last IOP has failed and the device is configured to pause on I/O errors
paused
guest has been paused via the ’stop’ command
postmigrate
guest is paused following a successful ’migrate’
prelaunch
QEMU was started with -S and guest has not started
restore-vm
guest is paused to restore VM state
running
guest is actively running
save-vm
guest is paused to save the VM state
shutdown
guest is shut down (and -no-shutdown is in use)
suspended
guest is suspended (ACPI S3)
watchdog
the watchdog action is configured to pause and has been triggered
guest-panicked
guest has been panicked as a result of guest OS panic
colo
guest is paused to save/restore VM state under colo checkpoint, VM can not get into this state unless colo capability is enabled for migration. (since 2.8)
preconfig
QEMU is paused before board specific init callback is executed. The state is reachable only if the –preconfig CLI option is used. (Since 3.0)
An enumeration of reasons for a Shutdown.
Values:
none
No shutdown request pending
host-error
An error prevents further use of guest
host-qmp-quit
Reaction to the QMP command ’quit’
host-qmp-system-reset
Reaction to the QMP command ’system_reset’
host-signal
Reaction to a signal, such as SIGINT
host-ui
Reaction to a UI event, like window close
guest-shutdown
Guest shutdown/suspend request, via ACPI or other hardware-specific means
guest-reset
Guest reset request, and command line turns that into a shutdown
guest-panic
Guest panicked, and command line turns that into a shutdown
subsystem-reset
Partial guest reset that does not trigger QMP events and ignores –no-reboot. This is useful for sanitizing hypercalls on s390 that are used during kexec/kdump/boot
Information about VCPU run state
Members:
running: boolean
true if all VCPUs are runnable, false if not runnable
singlestep: boolean
true if VCPUs are in single-step mode
status: RunState
the virtual machine RunState
Since: 0.14.0
Notes:
singlestep
is enabled through the GDB stub
Query the run status of all VCPUs
Returns:
StatusInfo
reflecting all VCPUs
Since: 0.14.0
Example:
-> { "execute": "query-status" } <- { "return": { "running": true, "singlestep": false, "status": "running" } }
Emitted when the virtual machine has shut down, indicating that qemu is about to exit.
Arguments:
guest: boolean
If true, the shutdown was triggered by a guest request (such as a guest-initiated ACPI shutdown request or other hardware-specific action) rather than a host request (such as sending qemu a SIGINT). (since 2.10)
reason: ShutdownCause
The ShutdownCause
which resulted in the SHUTDOWN. (since 4.0)
Note: If the command-line option "-no-shutdown" has been specified, qemu will not exit, and a STOP event will eventually follow the SHUTDOWN event
Since: 0.12.0
Example:
<- { "event": "SHUTDOWN", "data": { "guest": true }, "timestamp": { "seconds":<PHONE_NUMBER>, "microseconds": 682951 } }
Emitted when the virtual machine is powered down through the power control system, such as via ACPI.
Since: 0.12.0
Example:
<- { "event": "POWERDOWN", "timestamp": { "seconds":<PHONE_NUMBER>, "microseconds": 682951 } }
Emitted when the virtual machine is reset
Arguments:
guest: boolean
If true, the reset was triggered by a guest request (such as a guest-initiated ACPI reboot request or other hardware-specific action) rather than a host request (such as the QMP command system_reset). (since 2.10)
reason: ShutdownCause
The ShutdownCause
of the RESET. (since 4.0)
Since: 0.12.0
Example:
<- { "event": "RESET", "data": { "guest": false }, "timestamp": { "seconds":<PHONE_NUMBER>, "microseconds": 9518 } }
Emitted when the virtual machine is stopped
Since: 0.12.0
Example:
<- { "event": "STOP", "timestamp": { "seconds":<PHONE_NUMBER>, "microseconds": 281295 } }
Emitted when the virtual machine resumes execution
Since: 0.12.0
Example:
<- { "event": "RESUME", "timestamp": { "seconds":<PHONE_NUMBER>, "microseconds": 582542 } }
Emitted when guest enters a hardware suspension state, for example, S3 state, which is sometimes called standby state
Since: 1.1
Example:
<- { "event": "SUSPEND", "timestamp": { "seconds":<PHONE_NUMBER>, "microseconds": 309119 } }
Emitted when guest enters a hardware suspension state with data saved on disk, for example, S4 state, which is sometimes called hibernate state
Note:
QEMU shuts down (similar to event SHUTDOWN
) when entering this state
Since: 1.2
Example:
<- { "event": "SUSPEND_DISK", "timestamp": { "seconds":<PHONE_NUMBER>, "microseconds": 309119 } }
Emitted when the guest has woken up from suspend state and is running
Since: 1.1
Example:
<- { "event": "WAKEUP", "timestamp": { "seconds":<PHONE_NUMBER>, "microseconds": 745528 } }
Emitted when the watchdog device’s timer is expired
Arguments:
action: WatchdogAction
action that has been taken
Note: If action is "reset", "shutdown", or "pause" the WATCHDOG event is followed respectively by the RESET, SHUTDOWN, or STOP events
Note: This event is rate-limited.
Since: 0.13.0
Example:
<- { "event": "WATCHDOG", "data": { "action": "reset" }, "timestamp": { "seconds":<PHONE_NUMBER>, "microseconds": 959568 } }
An enumeration of the actions taken when the watchdog device’s timer is expired
Values:
reset
system resets
shutdown
system shutdown, note that it is similar to powerdown
, which
tries to set to system status and notify guest
poweroff
system poweroff, the emulator program exits
pause
system pauses, similar to stop
debug
system enters debug state
none
nothing is done
inject-nmi
a non-maskable interrupt is injected into the first VCPU (all VCPUS on x86) (since 2.4)
Since: 2.1
Set watchdog action
Arguments:
action: WatchdogAction
Not documented
Since: 2.11
Emitted when guest OS panic is detected
Arguments:
action: GuestPanicAction
action that has been taken, currently always "pause"
info: GuestPanicInformation
(optional)information about a panic (since 2.9)
Since: 1.5
Example:
<- { "event": "GUEST_PANICKED", "data": { "action": "pause" } }
Emitted when guest OS crash loaded is detected
Arguments:
action: GuestPanicAction
action that has been taken, currently always "run"
info: GuestPanicInformation
(optional)information about a panic
Since: 5.0
Example:
<- { "event": "GUEST_CRASHLOADED", "data": { "action": "run" } }
An enumeration of the actions taken when guest OS panic is detected
Values:
pause
system pauses
poweroff
Not documented
run
Not documented
Since: 2.1 (poweroff since 2.8, run since 5.0)
An enumeration of the guest panic information types
Values:
hyper-v
hyper-v guest panic information type
s390
s390 guest panic information type (Since: 2.12)
Since: 2.9
Information about a guest panic
Members:
type: GuestPanicInformationType
Crash type that defines the hypervisor specific information
GuestPanicInformationHyperV
when type
is "hyper-v"GuestPanicInformationS390
when type
is "s390"Since: 2.9
Hyper-V specific guest panic information (HV crash MSRs)
Members:
arg1: int
Not documented
arg2: int
Not documented
arg3: int
Not documented
arg4: int
Not documented
arg5: int
Not documented
Since: 2.9
Reason why the CPU is in a crashed state.
Values:
unknown
no crash reason was set
disabled-wait
the CPU has entered a disabled wait state
extint-loop
clock comparator or cpu timer interrupt with new PSW enabled for external interrupts
pgmint-loop
program interrupt with BAD new PSW
opint-loop
operation exception interrupt with invalid code at the program interrupt new PSW
Since: 2.12
S390 specific guest panic information (PSW)
Members:
core: int
core id of the CPU that crashed
psw-mask: int
control fields of guest PSW
psw-addr: int
guest instruction address
reason: S390CrashReason
guest crash reason
Since: 2.12
The type of network endpoint that will be using the credentials. Most types of credential require different setup / structures depending on whether they will be used in a server versus a client.
Values:
client
the network endpoint is acting as the client
server
the network endpoint is acting as the server
Since: 2.5
The data format that the secret is provided in
Values:
raw
raw bytes. When encoded in JSON only valid UTF-8 sequences can be used
base64
arbitrary base64 encoded binary data
Since: 2.6
The supported algorithms for computing content digests
Values:
md5
MD5. Should not be used in any new code, legacy compat only
sha1
SHA-1. Should not be used in any new code, legacy compat only
sha224
SHA-224. (since 2.7)
sha256
SHA-256. Current recommended strong hash.
sha384
SHA-384. (since 2.7)
sha512
SHA-512. (since 2.7)
ripemd160
RIPEMD-160. (since 2.7)
Since: 2.6
The supported algorithms for content encryption ciphers
Values:
aes-128
AES with 128 bit / 16 byte keys
aes-192
AES with 192 bit / 24 byte keys
aes-256
AES with 256 bit / 32 byte keys
des-rfb
RFB specific variant of single DES. Do not use except in VNC.
3des
3DES(EDE) with 192 bit / 24 byte keys (since 2.9)
cast5-128
Cast5 with 128 bit / 16 byte keys
serpent-128
Serpent with 128 bit / 16 byte keys
serpent-192
Serpent with 192 bit / 24 byte keys
serpent-256
Serpent with 256 bit / 32 byte keys
twofish-128
Twofish with 128 bit / 16 byte keys
twofish-192
Twofish with 192 bit / 24 byte keys
twofish-256
Twofish with 256 bit / 32 byte keys
Since: 2.6
The supported modes for content encryption ciphers
Values:
ecb
Electronic Code Book
cbc
Cipher Block Chaining
xts
XEX with tweaked code book and ciphertext stealing
ctr
Counter (Since 2.8)
Since: 2.6
The supported algorithms for generating initialization vectors for full disk encryption. The ’plain’ generator should not be used for disks with sector numbers larger than 2^32, except where compatibility with pre-existing Linux dm-crypt volumes is required.
Values:
plain
64-bit sector number truncated to 32-bits
plain64
64-bit sector number
essiv
64-bit sector number encrypted with a hash of the encryption key
Since: 2.6
The supported full disk encryption formats
Values:
qcow
QCow/QCow2 built-in AES-CBC encryption. Use only for liberating data from old images.
luks
LUKS encryption format. Recommended for new images
Since: 2.6
The common options that apply to all full disk encryption formats
Members:
format: QCryptoBlockFormat
the encryption format
Since: 2.6
The options that apply to QCow/QCow2 AES-CBC encryption format
Members:
key-secret: string
(optional)the ID of a QCryptoSecret object providing the decryption key. Mandatory except when probing image for metadata only.
Since: 2.6
The options that apply to LUKS encryption format
Members:
key-secret: string
(optional)the ID of a QCryptoSecret object providing the decryption key. Mandatory except when probing image for metadata only.
Since: 2.6
The options that apply to LUKS encryption format initialization
Members:
cipher-alg: QCryptoCipherAlgorithm
(optional)the cipher algorithm for data encryption Currently defaults to ’aes-256’.
cipher-mode: QCryptoCipherMode
(optional)the cipher mode for data encryption Currently defaults to ’xts’
ivgen-alg: QCryptoIVGenAlgorithm
(optional)the initialization vector generator Currently defaults to ’plain64’
ivgen-hash-alg: QCryptoHashAlgorithm
(optional)the initialization vector generator hash Currently defaults to ’sha256’
hash-alg: QCryptoHashAlgorithm
(optional)the master key hash algorithm Currently defaults to ’sha256’
iter-time: int
(optional)number of milliseconds to spend in PBKDF passphrase processing. Currently defaults to 2000. (since 2.8)
QCryptoBlockOptionsLUKS
Since: 2.6
The options that are available for all encryption formats when opening an existing volume
Members:
QCryptoBlockOptionsBase
QCryptoBlockOptionsQCow
when format
is "qcow"QCryptoBlockOptionsLUKS
when format
is "luks"Since: 2.6
The options that are available for all encryption formats when initializing a new volume
Members:
QCryptoBlockOptionsBase
QCryptoBlockOptionsQCow
when format
is "qcow"QCryptoBlockCreateOptionsLUKS
when format
is "luks"Since: 2.6
The common information that applies to all full disk encryption formats
Members:
format: QCryptoBlockFormat
the encryption format
Since: 2.7
Information about the LUKS block encryption key slot options
Members:
active: boolean
whether the key slot is currently in use
key-offset: int
offset to the key material in bytes
iters: int
(optional)number of PBKDF2 iterations for key material
stripes: int
(optional)number of stripes for splitting key material
Since: 2.7
Information about the LUKS block encryption options
Members:
cipher-alg: QCryptoCipherAlgorithm
the cipher algorithm for data encryption
cipher-mode: QCryptoCipherMode
the cipher mode for data encryption
ivgen-alg: QCryptoIVGenAlgorithm
the initialization vector generator
ivgen-hash-alg: QCryptoHashAlgorithm
(optional)the initialization vector generator hash
hash-alg: QCryptoHashAlgorithm
the master key hash algorithm
payload-offset: int
offset to the payload data in bytes
master-key-iters: int
number of PBKDF2 iterations for key material
uuid: string
unique identifier for the volume
slots: array of QCryptoBlockInfoLUKSSlot
information about each key slot
Since: 2.7
Information about the block encryption options
Members:
QCryptoBlockInfoBase
QCryptoBlockInfoLUKS
when format
is "luks"Since: 2.7
Defines state of keyslots that are affected by the update
Values:
active
The slots contain the given password and marked as active
inactive
The slots are erased (contain garbage) and marked as inactive
Since: 5.1
This struct defines the update parameters that activate/de-activate set of keyslots
Members:
state: QCryptoBlockLUKSKeyslotState
the desired state of the keyslots
new-secret: string
(optional)The ID of a QCryptoSecret object providing the password to be written into added active keyslots
old-secret: string
(optional)Optional (for deactivation only) If given will deactive all keyslots that match password located in QCryptoSecret with this ID
iter-time: int
(optional)Optional (for activation only) Number of milliseconds to spend in PBKDF passphrase processing for the newly activated keyslot. Currently defaults to 2000.
keyslot: int
(optional)Optional. ID of the keyslot to activate/deactivate. For keyslot activation, keyslot should not be active already (this is unsafe to update an active keyslot), but possible if ’force’ parameter is given. If keyslot is not given, first free keyslot will be written.
For keyslot deactivation, this parameter specifies the exact keyslot to deactivate
secret: string
(optional)Optional. The ID of a QCryptoSecret object providing the password to use to retrive current master key. Defaults to the same secret that was used to open the image
Since 5.1
The options that are available for all encryption formats when amending encryption settings
Members:
QCryptoBlockOptionsBase
QCryptoBlockAmendOptionsLUKS
when format
is "luks"Since: 5.1
Type of a background job.
Values:
commit
block commit job type, see "block-commit"
stream
block stream job type, see "block-stream"
mirror
drive mirror job type, see "drive-mirror"
backup
drive backup job type, see "drive-backup"
create
image creation job type, see "blockdev-create" (since 3.0)
amend
image options amend job type, see "x-blockdev-amend" (since 5.1)
Since: 1.7
Indicates the present state of a given job in its lifetime.
Values:
undefined
Erroneous, default state. Should not ever be visible.
created
The job has been created, but not yet started.
running
The job is currently running.
paused
The job is running, but paused. The pause may be requested by either the QMP user or by internal processes.
ready
The job is running, but is ready for the user to signal completion. This is used for long-running jobs like mirror that are designed to run indefinitely.
standby
The job is ready, but paused. This is nearly identical to paused
.
The job may return to ready
or otherwise be canceled.
waiting
The job is waiting for other jobs in the transaction to converge to the waiting state. This status will likely not be visible for the last job in a transaction.
pending
The job has finished its work, but has finalization steps that it
needs to make prior to completing. These changes will require
manual intervention via job-finalize
if auto-finalize was set to
false. These pending changes may still fail.
aborting
The job is in the process of being aborted, and will finish with
an error. The job will afterwards report that it is concluded
.
This status may not be visible to the management process.
concluded
The job has finished all work. If auto-dismiss was set to false,
the job will remain in the query list until it is dismissed via
job-dismiss
.
null
The job is in the process of being dismantled. This state should not ever be visible externally.
Since: 2.12
Represents command verbs that can be applied to a job.
Values:
cancel
see job-cancel
pause
see job-pause
resume
see job-resume
set-speed
see block-job-set-speed
complete
see job-complete
dismiss
see job-dismiss
finalize
see job-finalize
Since: 2.12
Emitted when a job transitions to a different status.
Arguments:
id: string
The job identifier
status: JobStatus
The new job status
Since: 3.0
Pause an active job.
This command returns immediately after marking the active job for pausing. Pausing an already paused job is an error.
The job will pause as soon as possible, which means transitioning into the PAUSED state if it was RUNNING, or into STANDBY if it was READY. The corresponding JOB_STATUS_CHANGE event will be emitted.
Cancelling a paused job automatically resumes it.
Arguments:
id: string
The job identifier.
Since: 3.0
Resume a paused job.
This command returns immediately after resuming a paused job. Resuming an already running job is an error.
id
: The job identifier.
Arguments:
id: string
Not documented
Since: 3.0
Instruct an active background job to cancel at the next opportunity. This command returns immediately after marking the active job for cancellation.
The job will cancel as soon as possible and then emit a JOB_STATUS_CHANGE event. Usually, the status will change to ABORTING, but it is possible that a job successfully completes (e.g. because it was almost done and there was no opportunity to cancel earlier than completing the job) and transitions to PENDING instead.
Arguments:
id: string
The job identifier.
Since: 3.0
Manually trigger completion of an active job in the READY state.
Arguments:
id: string
The job identifier.
Since: 3.0
Deletes a job that is in the CONCLUDED state. This command only needs to be run explicitly for jobs that don’t have automatic dismiss enabled.
This command will refuse to operate on any job that has not yet reached its terminal state, JOB_STATUS_CONCLUDED. For jobs that make use of JOB_READY event, job-cancel or job-complete will still need to be used as appropriate.
Arguments:
id: string
The job identifier.
Since: 3.0
Instructs all jobs in a transaction (or a single job if it is not part of any transaction) to finalize any graph changes and do any necessary cleanup. This command requires that all involved jobs are in the PENDING state.
For jobs in a transaction, instructing one job to finalize will force ALL jobs in the transaction to finalize, so it is only necessary to instruct a single member job to finalize.
Arguments:
id: string
The identifier of any job in the transaction, or of a job that is not part of any transaction.
Since: 3.0
Information about a job.
Members:
id: string
The job identifier
type: JobType
The kind of job that is being performed
status: JobStatus
Current job state/status
current-progress: int
Progress made until now. The unit is arbitrary and the
value can only meaningfully be used for the ratio of
current-progress
to total-progress
. The value is
monotonically increasing.
total-progress: int
Estimated current-progress
value at the completion of
the job. This value can arbitrarily change while the
job is running, in both directions.
error: string
(optional)If this field is present, the job failed; if it is still missing in the CONCLUDED state, this indicates successful completion.
The value is a human-readable error message to describe the reason for the job failure. It should not be parsed by applications.
Since: 3.0
Return information about jobs.
Returns:
a list with a JobInfo
for each active job
Since: 3.0
Members:
id: string
unique snapshot id
name: string
user chosen name
vm-state-size: int
size of the VM state
date-sec: int
UTC date of the snapshot in seconds
date-nsec: int
fractional part in nano seconds to be used with date-sec
vm-clock-sec: int
VM clock relative to boot in seconds
vm-clock-nsec: int
fractional part in nano seconds to be used with vm-clock-sec
Since: 1.3
Members:
format: BlockdevQcow2EncryptionFormat
The encryption format
Since: 2.10
Members:
ImageInfoSpecificQCow2EncryptionBase
QCryptoBlockInfoLUKS
when format
is "luks"Since: 2.10
Members:
compat: string
compatibility level
data-file: string
(optional)the filename of the external data file that is stored in the image and used as a default for opening the image (since: 4.0)
data-file-raw: boolean
(optional)True if the external data file must stay valid as a standalone (read-only) raw image without looking at qcow2 metadata (since: 4.0)
lazy-refcounts: boolean
(optional)on or off; only valid for compat >= 1.1
corrupt: boolean
(optional)true if the image has been marked corrupt; only valid for compat >= 1.1 (since 2.2)
refcount-bits: int
width of a refcount entry in bits (since 2.3)
encrypt: ImageInfoSpecificQCow2Encryption
(optional)details about encryption parameters; only set if image is encrypted (since 2.10)
bitmaps: array of Qcow2BitmapInfo
(optional)A list of qcow2 bitmap details (since 4.0)
compression-type: Qcow2CompressionType
the image cluster compression method (since 5.1)
Since: 1.7
Members:
create-type: string
The create type of VMDK image
cid: int
Content id of image
parent-cid: int
Parent VMDK image’s cid
extents: array of ImageInfo
List of extent files
Since: 1.7
A discriminated record of image format specific information structures.
Members:
type
One of "qcow2", "vmdk", "luks"
data: ImageInfoSpecificQCow2
when type
is "qcow2"data: ImageInfoSpecificVmdk
when type
is "vmdk"data: QCryptoBlockInfoLUKS
when type
is "luks"Since: 1.7
Information about a QEMU image file
Members:
filename: string
name of the image file
format: string
format of the image file
virtual-size: int
maximum capacity in bytes of the image
actual-size: int
(optional)actual size on disk in bytes of the image
dirty-flag: boolean
(optional)true if image is not cleanly closed
cluster-size: int
(optional)size of a cluster in bytes
encrypted: boolean
(optional)true if the image is encrypted
compressed: boolean
(optional)true if the image is compressed (Since 1.7)
backing-filename: string
(optional)name of the backing file
full-backing-filename: string
(optional)full path of the backing file
backing-filename-format: string
(optional)the format of the backing file
snapshots: array of SnapshotInfo
(optional)list of VM snapshots
backing-image: ImageInfo
(optional)info of the backing image (since 1.6)
format-specific: ImageInfoSpecific
(optional)structure supplying additional format-specific information (since 1.7)
Since: 1.3
Information about a QEMU image file check
Members:
filename: string
name of the image file checked
format: string
format of the image file checked
check-errors: int
number of unexpected errors occurred during check
image-end-offset: int
(optional)offset (in bytes) where the image ends, this field is present if the driver for the image format supports it
corruptions: int
(optional)number of corruptions found during the check if any
leaks: int
(optional)number of leaks found during the check if any
corruptions-fixed: int
(optional)number of corruptions fixed during the check if any
leaks-fixed: int
(optional)number of leaks fixed during the check if any
total-clusters: int
(optional)total number of clusters, this field is present if the driver for the image format supports it
allocated-clusters: int
(optional)total number of allocated clusters, this field is present if the driver for the image format supports it
fragmented-clusters: int
(optional)total number of fragmented clusters, this field is present if the driver for the image format supports it
compressed-clusters: int
(optional)total number of compressed clusters, this field is present if the driver for the image format supports it
Since: 1.4
Mapping information from a virtual block range to a host file range
Members:
start: int
the start byte of the mapped virtual range
length: int
the number of bytes of the mapped virtual range
data: boolean
whether the mapped range has data
zero: boolean
whether the virtual blocks are zeroed
depth: int
the depth of the mapping
offset: int
(optional)the offset in file that the virtual sectors are mapped to
filename: string
(optional)filename that is referred to by offset
Since: 2.6
Cache mode information for a block device
Members:
writeback: boolean
true if writeback mode is enabled
direct: boolean
true if the host page cache is bypassed (O_DIRECT)
no-flush: boolean
true if flush requests are ignored for the device
Since: 2.3
Information about the backing device for a block device.
Members:
file: string
the filename of the backing device
node-name: string
(optional)the name of the block driver node (Since 2.0)
ro: boolean
true if the backing device was open read-only
drv: string
the name of the block format used to open the backing device. As of 0.14.0 this can be: ’blkdebug’, ’bochs’, ’cloop’, ’cow’, ’dmg’, ’file’, ’file’, ’ftp’, ’ftps’, ’host_cdrom’, ’host_device’, ’http’, ’https’, ’luks’, ’nbd’, ’parallels’, ’qcow’, ’qcow2’, ’raw’, ’vdi’, ’vmdk’, ’vpc’, ’vvfat’ 2.2: ’archipelago’ added, ’cow’ dropped 2.3: ’host_floppy’ deprecated 2.5: ’host_floppy’ dropped 2.6: ’luks’ added 2.8: ’replication’ added, ’tftp’ dropped 2.9: ’archipelago’ dropped
backing_file: string
(optional)the name of the backing file (for copy-on-write)
backing_file_depth: int
number of files in the backing file chain (since: 1.2)
encrypted: boolean
true if the backing device is encrypted
encryption_key_missing: boolean
always false
detect_zeroes: BlockdevDetectZeroesOptions
detect and optimize zero writes (Since 2.1)
bps: int
total throughput limit in bytes per second is specified
bps_rd: int
read throughput limit in bytes per second is specified
bps_wr: int
write throughput limit in bytes per second is specified
iops: int
total I/O operations per second is specified
iops_rd: int
read I/O operations per second is specified
iops_wr: int
write I/O operations per second is specified
image: ImageInfo
the info of image used (since: 1.6)
bps_max: int
(optional)total throughput limit during bursts, in bytes (Since 1.7)
bps_rd_max: int
(optional)read throughput limit during bursts, in bytes (Since 1.7)
bps_wr_max: int
(optional)write throughput limit during bursts, in bytes (Since 1.7)
iops_max: int
(optional)total I/O operations per second during bursts, in bytes (Since 1.7)
iops_rd_max: int
(optional)read I/O operations per second during bursts, in bytes (Since 1.7)
iops_wr_max: int
(optional)write I/O operations per second during bursts, in bytes (Since 1.7)
bps_max_length: int
(optional)maximum length of the bps_max
burst
period, in seconds. (Since 2.6)
bps_rd_max_length: int
(optional)maximum length of the bps_rd_max
burst period, in seconds. (Since 2.6)
bps_wr_max_length: int
(optional)maximum length of the bps_wr_max
burst period, in seconds. (Since 2.6)
iops_max_length: int
(optional)maximum length of the iops
burst
period, in seconds. (Since 2.6)
iops_rd_max_length: int
(optional)maximum length of the iops_rd_max
burst period, in seconds. (Since 2.6)
iops_wr_max_length: int
(optional)maximum length of the iops_wr_max
burst period, in seconds. (Since 2.6)
iops_size: int
(optional)an I/O size in bytes (Since 1.7)
group: string
(optional)throttle group name (Since 2.4)
cache: BlockdevCacheInfo
the cache mode used for the block device (since: 2.3)
write_threshold: int
configured write threshold for the device. 0 if disabled. (Since 2.3)
dirty-bitmaps: array of BlockDirtyInfo
(optional)dirty bitmaps information (only present if node has one or more dirty bitmaps) (Since 4.2)
Features:
deprecated
Member encryption_key_missing
is deprecated. It is
always false.
Since: 0.14.0
An enumeration of block device I/O status.
Values:
ok
The last I/O operation has succeeded
failed
The last I/O operation has failed
nospace
The last I/O operation has failed due to a no-space condition
Since: 1.0
Entry in the metadata map of the device (returned by "qemu-img map")
Members:
start: int
Offset in the image of the first byte described by this entry (in bytes)
length: int
Length of the range described by this entry (in bytes)
depth: int
Number of layers (0 = top image, 1 = top image’s backing file, etc.) before reaching one for which the range is allocated. The value is in the range 0 to the depth of the image chain - 1.
zero: boolean
the sectors in this range read as zeros
data: boolean
reading the image will actually read data from a file (in particular,
if offset
is present this means that the sectors are not simply
preallocated, but contain actual data in raw format)
offset: int
(optional)if present, the image file stores the data for this range in raw format at the given offset.
Since: 1.7
An enumeration of possible states that a dirty bitmap can report to the user.
Values:
frozen
The bitmap is currently in-use by some operation and is immutable.
If the bitmap was active
prior to the operation, new writes by the
guest are being recorded in a temporary buffer, and will not be lost.
Generally, bitmaps are cleared on successful use in an operation and
the temporary buffer is committed into the bitmap. On failure, the
temporary buffer is merged back into the bitmap without first
clearing it.
Please refer to the documentation for each bitmap-using operation,
See also blockdev-backup
, drive-backup
.
disabled
The bitmap is not currently recording new writes by the guest.
This is requested explicitly via block-dirty-bitmap-disable
.
It can still be cleared, deleted, or used for backup operations.
active
The bitmap is actively monitoring for new writes, and can be cleared, deleted, or used for backup operations.
locked
The bitmap is currently in-use by some operation and is immutable.
If the bitmap was active
prior to the operation, it is still
recording new writes. If the bitmap was disabled
, it is not
recording new writes.  It can only be deleted.
Please rely on the inconsistent field in BlockDirtyInfo
instead, as the status field is deprecated. (Since 4.0)
Since: 2.4
Block dirty bitmap information.
 Replaces ‘active‘ and ‘disabled‘ statuses. (since 4.0)
busy: boolean
true if the bitmap is in-use by some operation (NBD or jobs) and cannot be modified via QMP or used by another operation. Replaces ‘locked‘ and ‘frozen‘ statuses. (since 4.0)
persistent: boolean
true if the bitmap was stored on disk, is scheduled to be stored on disk, or both. (since 4.0)
inconsistent: boolean
(optional)true if this is a persistent bitmap that was improperly
stored. Implies persistent
to be true; recording
and
busy
to be false. This bitmap cannot be used. To remove
it, use block-dirty-bitmap-remove
. (Since 4.0)
Features:
deprecated
Member status
is deprecated. Use recording
and
locked
instead.
Since: 1.3
An enumeration of flags that a bitmap can report to the user.
Values:
in-use
This flag is set by any process actively modifying the qcow2 file, and cleared when the updated bitmap is flushed to the qcow2 image. The presence of this flag in an offline image means that the bitmap was not saved correctly after its last usage, and may contain inconsistent data.
auto
The bitmap must reflect all changes of the virtual disk by any application that would write to this qcow2 file.
Since: 4.0
Qcow2 bitmap information.
Members:
name: string
the name of the bitmap
granularity: int
granularity of the bitmap in bytes
flags: array of Qcow2BitmapInfoFlags
flags of the bitmap
Since: 4.0
Block latency histogram.
Members:
boundaries: array of int
list of interval boundary values in nanoseconds, all greater than zero and in ascending order. For example, the list [10, 50, 100] produces the following histogram intervals: [0, 10), [10, 50), [50, 100), [100, +inf).
bins: array of int
list of io request counts corresponding to histogram intervals.
len(bins
) = len(boundaries
) + 1
For the example above, bins
may be something like [3, 1, 5, 2],
and corresponding histogram looks like:
5| *
4| *
3|
2| *
1|
+------------------
10 50 100
Since: 4.0
Block device information. This structure describes a virtual device and the backing device associated with it.
Members:
device: string
The device name associated with the virtual device.
qdev: string
(optional)The qdev ID, or if no ID is assigned, the QOM path of the block device. (since 2.10)
type: string
This field is returned only for compatibility reasons, it should not be used (always returns ’unknown’)
removable: boolean
True if the device supports removable media.
locked: boolean
True if the guest has locked this device from having its media removed
tray_open: boolean
(optional)True if the device’s tray is open (only present if it has a tray)
dirty-bitmaps: array of BlockDirtyInfo
(optional)dirty bitmaps information (only present if the driver has one or more dirty bitmaps) (Since 2.0)
io-status: BlockDeviceIoStatus
(optional)BlockDeviceIoStatus
. Only present if the device
supports it and the VM is configured to stop on errors
(supported device models: virtio-blk, IDE, SCSI except
scsi-generic)
inserted: BlockDeviceInfo
(optional)BlockDeviceInfo
describing the device if media is
present
Features:
deprecated
Member dirty-bitmaps
is deprecated. Use inserted
member dirty-bitmaps
instead.
Since: 0.14.0
Image file size calculation information. This structure describes the size requirements for creating a new image file.
The size requirements depend on the new image file format. File size always equals virtual disk size for the ’raw’ format, even for sparse POSIX files. Compact formats such as ’qcow2’ represent unallocated and zero regions efficiently so file size may be smaller than virtual disk size.
The values are upper bounds that are guaranteed to fit the new image file. Subsequent modification, such as internal snapshot or further bitmap creation, may require additional space and is not covered here.
Members:
required: int
Size required for a new image file, in bytes, when copying just allocated guest-visible contents.
fully-allocated: int
Image file size, in bytes, once data has been written to all sectors, when copying just guest-visible contents.
bitmaps: int
(optional)Additional size required if all the top-level bitmap metadata in the source image were to be copied to the destination, present only when source and destination both support persistent bitmaps. (since 5.1)
Since: 2.10
Get a list of BlockInfo for all virtual block devices.
Returns:
a list of BlockInfo
describing each virtual block device. Filter
nodes that were created implicitly are skipped over.
Since: 0.14.0
Example:
-> { "execute": "query-block" } <- { "return":[ { "io-status": "ok", "device":"ide0-hd0", "locked":false, "removable":false, "inserted":{ "ro":false, "drv":"qcow2", "encrypted":false, "file":"disks/test.qcow2", "backing_file_depth":1, "bps":1000000, "bps_rd":0, "bps_wr":0, "iops":1000000, "iops_rd":0, "iops_wr":0, "bps_max": 8000000, "bps_rd_max": 0, "bps_wr_max": 0, "iops_max": 0, "iops_rd_max": 0, "iops_wr_max": 0, "iops_size": 0, "detect_zeroes": "on", "write_threshold": 0, "image":{ "filename":"disks/test.qcow2", "format":"qcow2", "virtual-size":2048000, "backing_file":"base.qcow2", "full-backing-filename":"disks/base.qcow2", "backing-filename-format":"qcow2", "snapshots":[ { "id": "1", "name": "snapshot1", "vm-state-size": 0, "date-sec": 10000200, "date-nsec": 12, "vm-clock-sec": 206, "vm-clock-nsec": 30 } ], "backing-image":{ "filename":"disks/base.qcow2", "format":"qcow2", "virtual-size":2048000 } } }, "qdev": "ide_disk", "type":"unknown" }, { "io-status": "ok", "device":"ide1-cd0", "locked":false, "removable":true, "qdev": "/machine/unattached/device[23]", "tray_open": false, "type":"unknown" }, { "device":"floppy0", "locked":false, "removable":true, "qdev": "/machine/unattached/device[20]", "type":"unknown" }, { "device":"sd0", "locked":false, "removable":true, "type":"unknown" } ] }
Statistics of a block device during a given interval of time.
Members:
interval_length: int
Interval used for calculating the statistics, in seconds.
min_rd_latency_ns: int
Minimum latency of read operations in the defined interval, in nanoseconds.
min_wr_latency_ns: int
Minimum latency of write operations in the defined interval, in nanoseconds.
min_flush_latency_ns: int
Minimum latency of flush operations in the defined interval, in nanoseconds.
max_rd_latency_ns: int
Maximum latency of read operations in the defined interval, in nanoseconds.
max_wr_latency_ns: int
Maximum latency of write operations in the defined interval, in nanoseconds.
max_flush_latency_ns: int
Maximum latency of flush operations in the defined interval, in nanoseconds.
avg_rd_latency_ns: int
Average latency of read operations in the defined interval, in nanoseconds.
avg_wr_latency_ns: int
Average latency of write operations in the defined interval, in nanoseconds.
avg_flush_latency_ns: int
Average latency of flush operations in the defined interval, in nanoseconds.
avg_rd_queue_depth: number
Average number of pending read operations in the defined interval.
avg_wr_queue_depth: number
Average number of pending write operations in the defined interval.
Since: 2.5
Statistics of a virtual block device or a block backing device.
Members:
rd_bytes: int
The number of bytes read by the device.
wr_bytes: int
The number of bytes written by the device.
unmap_bytes: int
The number of bytes unmapped by the device (Since 4.2)
rd_operations: int
The number of read operations performed by the device.
wr_operations: int
The number of write operations performed by the device.
flush_operations: int
The number of cache flush operations performed by the device (since 0.15.0)
unmap_operations: int
The number of unmap operations performed by the device (Since 4.2)
rd_total_time_ns: int
Total time spent on reads in nanoseconds (since 0.15.0).
wr_total_time_ns: int
Total time spent on writes in nanoseconds (since 0.15.0).
flush_total_time_ns: int
Total time spent on cache flushes in nanoseconds (since 0.15.0).
unmap_total_time_ns: int
Total time spent on unmap operations in nanoseconds (Since 4.2)
wr_highest_offset: int
The offset after the greatest byte written to the device. The intended use of this information is for growable sparse files (like qcow2) that are used on top of a physical device.
rd_merged: int
Number of read requests that have been merged into another request (Since 2.3).
wr_merged: int
Number of write requests that have been merged into another request (Since 2.3).
unmap_merged: int
Number of unmap requests that have been merged into another request (Since 4.2)
idle_time_ns: int
(optional)Time since the last I/O operation, in nanoseconds. If the field is absent it means that there haven’t been any operations yet (Since 2.5).
failed_rd_operations: int
The number of failed read operations performed by the device (Since 2.5)
failed_wr_operations: int
The number of failed write operations performed by the device (Since 2.5)
failed_flush_operations: int
The number of failed flush operations performed by the device (Since 2.5)
failed_unmap_operations: int
The number of failed unmap operations performed by the device (Since 4.2)
invalid_rd_operations: int
The number of invalid read operations performed by the device (Since 2.5)
invalid_wr_operations: int
The number of invalid write operations performed by the device (Since 2.5)
invalid_flush_operations: int
The number of invalid flush operations performed by the device (Since 2.5)
invalid_unmap_operations: int
The number of invalid unmap operations performed by the device (Since 4.2)
account_invalid: boolean
Whether invalid operations are included in the last access statistics (Since 2.5)
account_failed: boolean
Whether failed operations are included in the latency and last access statistics (Since 2.5)
timed_stats: array of BlockDeviceTimedStats
Statistics specific to the set of previously defined intervals of time (Since 2.5)
rd_latency_histogram: BlockLatencyHistogramInfo
(optional)BlockLatencyHistogramInfo
. (Since 4.0)
wr_latency_histogram: BlockLatencyHistogramInfo
(optional)BlockLatencyHistogramInfo
. (Since 4.0)
flush_latency_histogram: BlockLatencyHistogramInfo
(optional)BlockLatencyHistogramInfo
. (Since 4.0)
Since: 0.14.0
File driver statistics
Members:
discard-nb-ok: int
The number of successful discard operations performed by the driver.
discard-nb-failed: int
The number of failed discard operations performed by the driver.
discard-bytes-ok: int
The number of bytes discarded by the driver.
Since: 4.2
Block driver specific statistics
Members:
driver: BlockdevDriver
Not documented
BlockStatsSpecificFile
when driver
is "file"BlockStatsSpecificFile
when driver
is "host_device"Since: 4.2
Statistics of a virtual block device or a block backing device.
Members:
device: string
(optional)If the stats are for a virtual block device, the name corresponding to the virtual block device.
node-name: string
(optional)The node name of the device. (Since 2.3)
qdev: string
(optional)The qdev ID, or if no ID is assigned, the QOM path of the block device. (since 3.0)
stats: BlockDeviceStats
A BlockDeviceStats
for the device.
driver-specific: BlockStatsSpecific
(optional)Optional driver-specific stats. (Since 4.2)
parent: BlockStats
(optional)This describes the file block device if it has one. Contains recursively the statistics of the underlying protocol (e.g. the host file for a qcow2 image). If there is no underlying protocol, this field is omitted
backing: BlockStats
(optional)This describes the backing block device if it has one. (Since 2.0)
Since: 0.14.0
Query the BlockStats
for all virtual block devices.
Arguments:
query-nodes: boolean
(optional)If true, the command will query all the block nodes that have a node name, in a list which will include "parent" information, but not "backing". If false or omitted, the behavior is as before - query all the device backends, recursively including their "parent" and "backing". Filter nodes that were created implicitly are skipped over in this mode. (Since 2.3)
Returns:
A list of BlockStats
for each virtual block devices.
Since: 0.14.0
Example:
-> { "execute": "query-blockstats" } <- { "return":[ { "device":"ide0-hd0", "parent":{ "stats":{ "wr_highest_offset":3686448128, "wr_bytes":9786368, "wr_operations":751, "rd_bytes":122567168, "rd_operations":36772 "wr_total_times_ns":313253456 "rd_total_times_ns":3465673657 "flush_total_times_ns":49653 "flush_operations":61, "rd_merged":0, "wr_merged":0, "idle_time_ns":2953431879, "account_invalid":true, "account_failed":false } }, "stats":{ "wr_highest_offset":2821110784, "wr_bytes":9786368, "wr_operations":692, "rd_bytes":122739200, "rd_operations":36604 "flush_operations":51, "wr_total_times_ns":313253456 "rd_total_times_ns":3465673657 "flush_total_times_ns":49653, "rd_merged":0, "wr_merged":0, "idle_time_ns":2953431879, "account_invalid":true, "account_failed":false }, "qdev": "/machine/unattached/device[23]" }, { "device":"ide1-cd0", "stats":{ "wr_highest_offset":0, "wr_bytes":0, "wr_operations":0, "rd_bytes":0, "rd_operations":0 "flush_operations":0, "wr_total_times_ns":0 "rd_total_times_ns":0 "flush_total_times_ns":0, "rd_merged":0, "wr_merged":0, "account_invalid":false, "account_failed":false }, "qdev": "/machine/unattached/device[24]" }, { "device":"floppy0", "stats":{ "wr_highest_offset":0, "wr_bytes":0, "wr_operations":0, "rd_bytes":0, "rd_operations":0 "flush_operations":0, "wr_total_times_ns":0 "rd_total_times_ns":0 "flush_total_times_ns":0, "rd_merged":0, "wr_merged":0, "account_invalid":false, "account_failed":false }, "qdev": "/machine/unattached/device[16]" }, { "device":"sd0", "stats":{ "wr_highest_offset":0, "wr_bytes":0, "wr_operations":0, "rd_bytes":0, "rd_operations":0 "flush_operations":0, "wr_total_times_ns":0 "rd_total_times_ns":0 "flush_total_times_ns":0, "rd_merged":0, "wr_merged":0, "account_invalid":false, "account_failed":false } } ] }
An enumeration of possible behaviors for errors on I/O operations. The exact meaning depends on whether the I/O was initiated by a guest or by a block job
Values:
report
for guest operations, report the error to the guest; for jobs, cancel the job
ignore
ignore the error, only report a QMP event (BLOCK_IO_ERROR or BLOCK_JOB_ERROR). The backup, mirror and commit block jobs retry the failing request later and may still complete successfully. The stream block job continues to stream and will complete with an error.
enospc
same as stop
on ENOSPC, same as report
otherwise.
stop
for guest operations, stop the virtual machine; for jobs, pause the job
auto
inherit the error handling policy of the backend (since: 2.7)
Since: 1.3
An enumeration of possible behaviors for the initial synchronization phase of storage mirroring.
Values:
top
copies data in the topmost image to the destination
full
copies data from all images to the destination
none
only copy data written from now on
incremental
only copy data described by the dirty bitmap. (since: 2.4)
bitmap
only copy data described by the dirty bitmap. (since: 4.2) Behavior on completion is determined by the BitmapSyncMode.
Since: 1.3
An enumeration of possible behaviors for the synchronization of a bitmap when used for data copy operations.
Values:
on-success
The bitmap is only synced when the operation is successful. This is the behavior always used for ’INCREMENTAL’ backups.
never
The bitmap is never synchronized with the operation, and is treated solely as a read-only manifest of blocks to copy.
always
The bitmap is always synchronized with the operation, regardless of whether or not the operation was successful.
Since: 4.2
An enumeration whose values tell the mirror block job when to trigger writes to the target.
Values:
background
copy data in background only.
write-blocking
when data is written to the source, write it
(synchronously) to the target as well. In
addition, data is copied in background just like in
background
mode.
Since: 3.0
Information about a long-running block device operation.
Members:
type: string
the job type (’stream’ for image streaming)
device: string
The job identifier. Originally the device name but other values are allowed since QEMU 2.7
len: int
Estimated offset
value at the completion of the job. This value can
arbitrarily change while the job is running, in both directions.
offset: int
Progress made until now. The unit is arbitrary and the value can
only meaningfully be used for the ratio of offset
to len
. The
value is monotonically increasing.
busy: boolean
false if the job is known to be in a quiescent state, with no pending I/O. Since 1.3.
paused: boolean
whether the job is paused or, if busy
is true, will
pause itself as soon as possible. Since 1.3.
speed: int
the rate limit, bytes per second
io-status: BlockDeviceIoStatus
the status of the job (since 1.3)
ready: boolean
true if the job may be completed (since 2.2)
status: JobStatus
Current job state/status (since 2.12)
auto-finalize: boolean
Job will finalize itself when PENDING, moving to the CONCLUDED state. (since 2.12)
auto-dismiss: boolean
Job will dismiss itself when CONCLUDED, moving to the NULL state and disappearing from the query list. (since 2.12)
error: string
(optional)Error information if the job did not complete successfully. Not set if the job completed successfully. (since 2.12.1)
Since: 1.1
Return information about long-running block device operations.
Returns:
a list of BlockJobInfo
for each active block job
Since: 1.1
This command sets the password of a block device that has not been open with a password and requires one.
This command is now obsolete and will always return an error since 2.10
Arguments:
device: string
(optional)Not documented
node-name: string
(optional)Not documented
password: string
Not documented
Resize a block image while a guest is running.
Either device
or node-name
must be set but not both.
Arguments:
device: string
(optional)the name of the device to get the image resized
node-name: string
(optional)graph node name to get the image resized (Since 2.0)
size: int
new image size in bytes
Returns:
device
is not a valid block device, DeviceNotFound
Since: 0.14.0
Example:
-> { "execute": "block_resize", "arguments": { "device": "scratch", "size":<PHONE_NUMBER> } } <- { "return": {} }
An enumeration that tells QEMU how to set the backing file path in a new image file.
Values:
existing
QEMU should look for an existing image file.
absolute-paths
QEMU should create a new image with absolute paths for the backing file. If there is no backing file available, the new image will not be backed either.
Since: 1.1
Either device
or node-name
must be set but not both.
Members:
device: string
(optional)the name of the device to take a snapshot of.
node-name: string
(optional)graph node name to generate the snapshot from (Since 2.0)
snapshot-file: string
the target of the new overlay image. If the file exists, or if it is a device, the overlay will be created in the existing file/device. Otherwise, a new file will be created.
snapshot-node-name: string
(optional)the graph node name of the new image (Since 2.0)
format: string
(optional)the format of the overlay image, default is ’qcow2’.
mode: NewImageMode
(optional)whether and how QEMU should create a new image, default is ’absolute-paths’.
Members:
node: string
device or node name that will have a snapshot taken.
overlay: string
reference to the existing block device that will become
the overlay of node
, as part of taking the snapshot.
It must not have a current backing file (this can be
achieved by passing "backing": null to blockdev-add).
Since: 2.5
Members:
job-id: string
(optional)identifier for the newly-created block job. If omitted, the device name will be used. (Since 2.7)
device: string
the device name or node-name of a root node which should be copied.
sync: MirrorSyncMode
what parts of the disk image should be copied to the destination (all the disk, only the sectors allocated in the topmost image, from a dirty bitmap, or only new I/O).
speed: int
(optional)the maximum speed, in bytes per second. The default is 0, for unlimited.
bitmap: string
(optional)The name of a dirty bitmap to use. Must be present if sync is "bitmap" or "incremental". Can be present if sync is "full" or "top". Must not be present otherwise. (Since 2.4 (drive-backup), 3.1 (blockdev-backup))
bitmap-mode: BitmapSyncMode
(optional)Specifies the type of data the bitmap should contain after the operation concludes. Must be present if a bitmap was provided, Must NOT be present otherwise. (Since 4.2)
compress: boolean
(optional)true to compress data, if the target format supports it. (default: false) (since 2.8)
on-source-error: BlockdevOnError
(optional)the action to take on an error on the source, default ’report’. ’stop’ and ’enospc’ can only be used if the block device supports io-status (see BlockInfo).
on-target-error: BlockdevOnError
(optional)the action to take on an error on the target,
default ’report’ (no limitations, since this applies to
a different block device than device
).
auto-finalize: boolean
(optional)When false, this job will wait in a PENDING state after it has
finished its work, waiting for block-job-finalize
before
making any block graph changes.
When true, this job will automatically
perform its abort or commit actions.
Defaults to true. (Since 2.12)
auto-dismiss: boolean
(optional)When false, this job will wait in a CONCLUDED state after it
has completely ceased all work, and awaits block-job-dismiss
.
When true, this job will automatically disappear from the query
list without user intervention.
Defaults to true. (Since 2.12)
filter-node-name: string
(optional)the node name that should be assigned to the
filter driver that the backup job inserts into the graph
above node specified by drive
. If this option is not given,
a node name is autogenerated. (Since: 4.2)
Note:
on-source-error
and on-target-error
only affect background
I/O. If an error occurs during a guest write request, the device’s
rerror/werror actions will be used.
Since: 4.2
Members:
target: string
the target of the new image. If the file exists, or if it is a device, the existing file/device will be used as the new destination. If it does not exist, a new file will be created.
format: string
(optional)the format of the new destination, default is to
probe if mode
is ’existing’, else the format of the source
mode: NewImageMode
(optional)whether and how QEMU should create a new image, default is ’absolute-paths’.
BackupCommon
Since: 1.6
Members:
target: string
the device name or node-name of the backup target node.
BackupCommon
Since: 2.3
Takes a synchronous snapshot of a block device.
For the arguments, see the documentation of BlockdevSnapshotSync.
Returns:
device
is not a valid block device, DeviceNotFound
Since: 0.14.0
Example:
-> { "execute": "blockdev-snapshot-sync", "arguments": { "device": "ide-hd0", "snapshot-file": "/some/place/my-image", "format": "qcow2" } } <- { "return": {} }
Takes a snapshot of a block device.
Take a snapshot, by installing ’node’ as the backing image of ’overlay’. Additionally, if ’node’ is associated with a block device, the block device changes to using ’overlay’ as its new active image.
For the arguments, see the documentation of BlockdevSnapshot.
Features:
allow-write-only-overlay
If present, the check whether this operation is safe was relaxed so that it can be used to change backing file of a destination of a blockdev-mirror. (since 5.0)
Since: 2.5
Example:
-> { "execute": "blockdev-add", "arguments": { "driver": "qcow2", "node-name": "node1534", "file": { "driver": "file", "filename": "hd1.qcow2" }, "backing": null } } <- { "return": {} } -> { "execute": "blockdev-snapshot", "arguments": { "node": "ide-hd0", "overlay": "node1534" } } <- { "return": {} }
Change the backing file in the image file metadata. This does not cause QEMU to reopen the image file to reparse the backing filename (it may, however, perform a reopen to change permissions from r/o -> r/w -> r/o, if needed). The new backing file string is written into the image file metadata, and the QEMU internal strings are updated.
Arguments:
image-node-name: string
The name of the block driver state node of the image to modify. The "device" argument is used to verify "image-node-name" is in the chain described by "device".
device: string
The device name or node-name of the root node that owns image-node-name.
backing-file: string
The string to write as the backing file. This string is not validated, so care should be taken when specifying the string or the image chain may not be able to be reopened again.
Returns:
Since: 2.1
Live commit of data from overlay image nodes into backing nodes - i.e., writes data between ’top’ and ’base’ into ’base’.
Arguments:
job-id: string
(optional)identifier for the newly-created block job. If omitted, the device name will be used. (Since 2.7)
device: string
the device name or node-name of a root node
base-node: string
(optional)The node name of the backing image to write data into. If not specified, this is the deepest backing image. (since: 3.1)
base: string
(optional)Same as base-node
, except that it is a file name rather than a node
name. This must be the exact filename string that was used to open the
node; other strings, even if addressing the same file, are not
accepted
top-node: string
(optional)The node name of the backing image within the image chain which contains the topmost data to be committed down. If not specified, this is the active layer. (since: 3.1)
top: string
(optional)Same as top-node
, except that it is a file name rather than a node
name. This must be the exact filename string that was used to open the
node; other strings, even if addressing the same file, are not
accepted
backing-file: string
(optional)The backing file string to write into the overlay image of ’top’. If ’top’ is the active layer, specifying a backing file string is an error. This filename is not validated.
If a pathname string is such that it cannot be resolved by QEMU, that means that subsequent QMP or HMP commands must use node-names for the image in question, as filename lookup methods will fail.
If not specified, QEMU will automatically determine the backing file string to use, or error out if there is no obvious choice. Care should be taken when specifying the string, to specify a valid filename or protocol. (Since 2.1)
If top == base, that is an error. If top == active, the job will not be completed by itself, user needs to complete the job with the block-job-complete command after getting the ready event. (Since 2.0)
If the base image is smaller than top, then the base image will be resized to be the same size as top. If top is smaller than the base image, the base will not be truncated. If you want the base image size to match the size of the smaller top, you can safely truncate it yourself once the commit operation successfully completes.
speed: int
(optional)the maximum speed, in bytes per second
on-error: BlockdevOnError
(optional)the action to take on an error. ’ignore’ means that the request should be retried. (default: report; Since: 5.0)
filter-node-name: string
(optional)the node name that should be assigned to the
filter driver that the commit job inserts into the graph
above top
. If this option is not given, a node name is
autogenerated. (Since: 2.9)
auto-finalize: boolean
(optional)When false, this job will wait in a PENDING state after it has
finished its work, waiting for block-job-finalize
before
making any block graph changes.
When true, this job will automatically
perform its abort or commit actions.
Defaults to true. (Since 3.1)
auto-dismiss: boolean
(optional)When false, this job will wait in a CONCLUDED state after it
has completely ceased all work, and awaits block-job-dismiss
.
When true, this job will automatically disappear from the query
list without user intervention.
Defaults to true. (Since 3.1)
Features:
deprecated
Members base
and top
are deprecated. Use base-node
and top-node
instead.
Returns:
device
does not exist, DeviceNotFound
Since: 1.3
Example:
-> { "execute": "block-commit", "arguments": { "device": "virtio0", "top": "/tmp/snap1.qcow2" } } <- { "return": {} }
Start a point-in-time copy of a block device to a new destination. The status of ongoing drive-backup operations can be checked with query-block-jobs where the BlockJobInfo.type field has the value ’backup’. The operation can be stopped before it has completed using the block-job-cancel command.
Arguments: the members of DriveBackup
Returns:
device
is not a valid block device, GenericError
Since: 1.6
Example:
-> { "execute": "drive-backup", "arguments": { "device": "drive0", "sync": "full", "target": "backup.img" } } <- { "return": {} }
Start a point-in-time copy of a block device to a new destination. The status of ongoing blockdev-backup operations can be checked with query-block-jobs where the BlockJobInfo.type field has the value ’backup’. The operation can be stopped before it has completed using the block-job-cancel command.
Arguments: the members of BlockdevBackup
Returns:
device
is not a valid block device, DeviceNotFound
Since: 2.3
Example:
-> { "execute": "blockdev-backup", "arguments": { "device": "src-id", "sync": "full", "target": "tgt-id" } } <- { "return": {} }
Get the named block driver list
Arguments:
flat: boolean
(optional)Omit the nested data about backing image ("backing-image" key) if true. Default is false (Since 5.0)
Returns: the list of BlockDeviceInfo
Since: 2.0
Example:
-> { "execute": "query-named-block-nodes" } <- { "return": [ { "ro":false, "drv":"qcow2", "encrypted":false, "file":"disks/test.qcow2", "node-name": "my-node", "backing_file_depth":1, "bps":1000000, "bps_rd":0, "bps_wr":0, "iops":1000000, "iops_rd":0, "iops_wr":0, "bps_max": 8000000, "bps_rd_max": 0, "bps_wr_max": 0, "iops_max": 0, "iops_rd_max": 0, "iops_wr_max": 0, "iops_size": 0, "write_threshold": 0, "image":{ "filename":"disks/test.qcow2", "format":"qcow2", "virtual-size":2048000, "backing_file":"base.qcow2", "full-backing-filename":"disks/base.qcow2", "backing-filename-format":"qcow2", "snapshots":[ { "id": "1", "name": "snapshot1", "vm-state-size": 0, "date-sec": 10000200, "date-nsec": 12, "vm-clock-sec": 206, "vm-clock-nsec": 30 } ], "backing-image":{ "filename":"disks/base.qcow2", "format":"qcow2", "virtual-size":2048000 } } } ] }
Values:
block-backend
corresponds to BlockBackend
block-job
corresonds to BlockJob
block-driver
corresponds to BlockDriverState
Since: 4.0
Members:
id: int
Block graph node identifier. This id
is generated only for
x-debug-query-block-graph and does not relate to any other identifiers in
Qemu.
type: XDbgBlockGraphNodeType
Type of graph node. Can be one of block-backend, block-job or block-driver-state.
name: string
Human readable name of the node. Corresponds to node-name for block-driver-state nodes; is not guaranteed to be unique in the whole graph (with block-jobs and block-backends).
Since: 4.0
Enum of base block permissions.
Values:
consistent-read
A user that has the "permission" of consistent reads is guaranteed that their view of the contents of the block device is complete and self-consistent, representing the contents of a disk at a specific point. For most block devices (including their backing files) this is true, but the property cannot be maintained in a few situations like for intermediate nodes of a commit block job.
write
This permission is required to change the visible disk contents.
write-unchanged
This permission (which is weaker than BLK_PERM_WRITE) is both enough and required for writes to the block node when the caller promises that the visible disk content doesn’t change. As the BLK_PERM_WRITE permission is strictly stronger, either is sufficient to perform an unchanging write.
resize
This permission is required to change the size of a block node.
graph-mod
This permission is required to change the node that this BdrvChild points to.
Since: 4.0
Block Graph edge description for x-debug-query-block-graph.
Members:
parent: int
parent id
child: int
child id
name: string
name of the relation (examples are ’file’ and ’backing’)
perm: array of BlockPermission
granted permissions for the parent operating on the child
shared-perm: array of BlockPermission
permissions that can still be granted to other users of the child while it is still attached to this parent
Since: 4.0
Block Graph - list of nodes and list of edges.
Members:
nodes: array of XDbgBlockGraphNode
Not documented
edges: array of XDbgBlockGraphEdge
Not documented
Since: 4.0
Get the block graph.
Since: 4.0
Start mirroring a block device’s writes to a new destination. target specifies the target of the new image. If the file exists, or if it is a device, it will be used as the new destination for writes. If it does not exist, a new file will be created. format specifies the format of the mirror image, default is to probe if mode=’existing’, else the format of the source.
Arguments: the members of DriveMirror
Returns:
device
is not a valid block device, GenericError
Since: 1.3
Example:
-> { "execute": "drive-mirror", "arguments": { "device": "ide-hd0", "target": "/some/place/my-image", "sync": "full", "format": "qcow2" } } <- { "return": {} }
A set of parameters describing drive mirror setup.
Members:
job-id: string
(optional)identifier for the newly-created block job. If omitted, the device name will be used. (Since 2.7)
device: string
the device name or node-name of a root node whose writes should be mirrored.
target: string
the target of the new image. If the file exists, or if it is a device, the existing file/device will be used as the new destination. If it does not exist, a new file will be created.
format: string
(optional)the format of the new destination, default is to
probe if mode
is ’existing’, else the format of the source
node-name: string
(optional)the new block driver state node name in the graph (Since 2.1)
replaces: string
(optional)with sync=full graph node name to be replaced by the new image when a whole image copy is done. This can be used to repair broken Quorum files. (Since 2.1)
mode: NewImageMode
(optional)whether and how QEMU should create a new image, default is ’absolute-paths’.
speed: int
(optional)the maximum speed, in bytes per second
sync: MirrorSyncMode
what parts of the disk image should be copied to the destination (all the disk, only the sectors allocated in the topmost image, or only new I/O).
granularity: int
(optional)granularity of the dirty bitmap, default is 64K if the image format doesn’t have clusters, 4K if the clusters are smaller than that, else the cluster size. Must be a power of 2 between 512 and 64M (since 1.4).
buf-size: int
(optional)maximum amount of data in flight from source to target (since 1.4).
on-source-error: BlockdevOnError
(optional)the action to take on an error on the source, default ’report’. ’stop’ and ’enospc’ can only be used if the block device supports io-status (see BlockInfo).
on-target-error: BlockdevOnError
(optional)the action to take on an error on the target,
default ’report’ (no limitations, since this applies to
a different block device than device
).
unmap: boolean
(optional)Whether to try to unmap target sectors where source has only zero. If true, and target unallocated sectors will read as zero, target image sectors will be unmapped; otherwise, zeroes will be written. Both will result in identical contents. Default is true. (Since 2.4)
copy-mode: MirrorCopyMode
(optional)when to copy data to the destination; defaults to ’background’ (Since: 3.0)
auto-finalize: boolean
(optional)When false, this job will wait in a PENDING state after it has
finished its work, waiting for block-job-finalize
before
making any block graph changes.
When true, this job will automatically
perform its abort or commit actions.
Defaults to true. (Since 3.1)
auto-dismiss: boolean
(optional)When false, this job will wait in a CONCLUDED state after it
has completely ceased all work, and awaits block-job-dismiss
.
When true, this job will automatically disappear from the query
list without user intervention.
Defaults to true. (Since 3.1)
Since: 1.3
Members:
node: string
name of device/node which the bitmap is tracking
name: string
name of the dirty bitmap
Since: 2.4
Members:
node: string
name of device/node which the bitmap is tracking
name: string
name of the dirty bitmap (must be less than 1024 bytes)
granularity: int
(optional)the bitmap granularity, default is 64k for block-dirty-bitmap-add
persistent: boolean
(optional)the bitmap is persistent, i.e. it will be saved to the corresponding block device image file on its close. For now only Qcow2 disks support persistent bitmaps. Default is false for block-dirty-bitmap-add. (Since: 2.10)
disabled: boolean
(optional)the bitmap is created in the disabled state, which means that it will not track drive changes. The bitmap may be enabled with block-dirty-bitmap-enable. Default is false. (Since: 4.0)
Since: 2.4
Members:
local: string
name of the bitmap, attached to the same node as target bitmap.
external: BlockDirtyBitmap
bitmap with specified node
Since: 4.1
Members:
node: string
name of device/node which the target
bitmap is tracking
target: string
name of the destination dirty bitmap
bitmaps: array of BlockDirtyBitmapMergeSource
name(s) of the source dirty bitmap(s) at node
and/or fully
specifed BlockDirtyBitmap elements. The latter are supported
since 4.1.
Since: 4.0
Create a dirty bitmap with a name on the node, and start tracking the writes.
 If the bitmap is persistent, remove it from its storage too.
Returns:
node
is not a valid block device or node, DeviceNotFound
name
is not found, GenericError with an explanation
name
is frozen by an operation, GenericError
Since: 2.4
Example:
-> { "execute": "block-dirty-bitmap-remove", "arguments": { "node": "drive0", "name": "bitmap0" } } <- { "return": {} }
Clear (reset) a dirty bitmap on the device, so that an incremental backup from this point in time forward will only backup clusters modified after this clear operation.
Returns:
node
is not a valid block device, DeviceNotFound
name
is not found, GenericError with an explanation
Since: 2.4
Example:
-> { "execute": "block-dirty-bitmap-clear", "arguments": { "node": "drive0", "name": "bitmap0" } } <- { "return": {} }
Enables a dirty bitmap so that it will begin tracking disk changes.
Returns:
node
is not a valid block device, DeviceNotFound
name
is not found, GenericError with an explanation
Since: 4.0
Example:
-> { "execute": "block-dirty-bitmap-enable", "arguments": { "node": "drive0", "name": "bitmap0" } } <- { "return": {} }
Disables a dirty bitmap so that it will stop tracking disk changes.
Returns:
node
is not a valid block device, DeviceNotFound
name
is not found, GenericError with an explanation
Since: 4.0
Example:
-> { "execute": "block-dirty-bitmap-disable", "arguments": { "node": "drive0", "name": "bitmap0" } } <- { "return": {} }
Merge dirty bitmaps listed in bitmaps
to the target
dirty bitmap.
Dirty bitmaps in bitmaps
will be unchanged, except if it also appears
as the target
bitmap. Any bits already set in target
will still be
set after the merge, i.e., this operation does not clear the target.
On error, target
is unchanged.
The resulting bitmap will count as dirty any clusters that were dirty in any of the source bitmaps. This can be used to achieve backup checkpoints, or in simpler usages, to copy bitmaps.
Returns:
node
is not a valid block device, DeviceNotFound
bitmaps
or target
is not found, GenericError
Since: 4.0
Example:
-> { "execute": "block-dirty-bitmap-merge", "arguments": { "node": "drive0", "target": "bitmap0", "bitmaps": ["bitmap1"] } } <- { "return": {} }
SHA256 hash of dirty bitmap data
Members:
sha256: string
ASCII representation of SHA256 bitmap hash
Since: 2.10
Get bitmap SHA256.
Returns:
node
is not a valid block device, DeviceNotFound
name
is not found or if hashing has failed, GenericError with an
explanation
Since: 2.10
Start mirroring a block device’s writes to a new destination.
Arguments:
job-id: string
(optional)identifier for the newly-created block job. If omitted, the device name will be used. (Since 2.7)
device: string
The device name or node-name of a root node whose writes should be mirrored.
target: string
the id or node-name of the block device to mirror to. This mustn’t be attached to guest.
replaces: string
(optional)with sync=full graph node name to be replaced by the new image when a whole image copy is done. This can be used to repair broken Quorum files.
speed: int
(optional)the maximum speed, in bytes per second
sync: MirrorSyncMode
what parts of the disk image should be copied to the destination (all the disk, only the sectors allocated in the topmost image, or only new I/O).
granularity: int
(optional)granularity of the dirty bitmap, default is 64K if the image format doesn’t have clusters, 4K if the clusters are smaller than that, else the cluster size. Must be a power of 2 between 512 and 64M
buf-size: int
(optional)maximum amount of data in flight from source to target
on-source-error: BlockdevOnError
(optional)the action to take on an error on the source, default ’report’. ’stop’ and ’enospc’ can only be used if the block device supports io-status (see BlockInfo).
on-target-error: BlockdevOnError
(optional)the action to take on an error on the target,
default ’report’ (no limitations, since this applies to
a different block device than device
).
filter-node-name: string
(optional)the node name that should be assigned to the
filter driver that the mirror job inserts into the graph
above device
. If this option is not given, a node name is
autogenerated. (Since: 2.9)
copy-mode: MirrorCopyMode
(optional)when to copy data to the destination; defaults to ’background’ (Since: 3.0)
auto-finalize: boolean
(optional)When false, this job will wait in a PENDING state after it has
finished its work, waiting for block-job-finalize
before
making any block graph changes.
When true, this job will automatically
perform its abort or commit actions.
Defaults to true. (Since 3.1)
auto-dismiss: boolean
(optional)When false, this job will wait in a CONCLUDED state after it
has completely ceased all work, and awaits block-job-dismiss
.
When true, this job will automatically disappear from the query
list without user intervention.
Defaults to true. (Since 3.1)
Returns: nothing on success.
Since: 2.6
Example:
-> { "execute": "blockdev-mirror", "arguments": { "device": "ide-hd0", "target": "target0", "sync": "full" } } <- { "return": {} }
A set of parameters describing block throttling.
Members:
device: string
(optional)Block device name
id: string
(optional)The name or QOM path of the guest device (since: 2.8)
bps: int
total throughput limit in bytes per second
bps_rd: int
read throughput limit in bytes per second
bps_wr: int
write throughput limit in bytes per second
iops: int
total I/O operations per second
iops_rd: int
read I/O operations per second
iops_wr: int
write I/O operations per second
bps_max: int
(optional)total throughput limit during bursts, in bytes (Since 1.7)
bps_rd_max: int
(optional)read throughput limit during bursts, in bytes (Since 1.7)
bps_wr_max: int
(optional)write throughput limit during bursts, in bytes (Since 1.7)
iops_max: int
(optional)total I/O operations per second during bursts, in bytes (Since 1.7)
iops_rd_max: int
(optional)read I/O operations per second during bursts, in bytes (Since 1.7)
iops_wr_max: int
(optional)write I/O operations per second during bursts, in bytes (Since 1.7)
bps_max_length: int
(optional)maximum length of the bps_max
burst
period, in seconds. It must only
be set if bps_max
is set as well.
Defaults to 1. (Since 2.6)
bps_rd_max_length: int
(optional)maximum length of the bps_rd_max
burst period, in seconds. It must only
be set if bps_rd_max
is set as well.
Defaults to 1. (Since 2.6)
bps_wr_max_length: int
(optional)maximum length of the bps_wr_max
burst period, in seconds. It must only
be set if bps_wr_max
is set as well.
Defaults to 1. (Since 2.6)
iops_max_length: int
(optional)maximum length of the iops
burst
period, in seconds. It must only
be set if iops_max
is set as well.
Defaults to 1. (Since 2.6)
iops_rd_max_length: int
(optional)maximum length of the iops_rd_max
burst period, in seconds. It must only
be set if iops_rd_max
is set as well.
Defaults to 1. (Since 2.6)
iops_wr_max_length: int
(optional)maximum length of the iops_wr_max
burst period, in seconds. It must only
be set if iops_wr_max
is set as well.
Defaults to 1. (Since 2.6)
iops_size: int
(optional)an I/O size in bytes (Since 1.7)
group: string
(optional)throttle group name (Since 2.4)
Features:
deprecated
Member device
is deprecated. Use id
instead.
Since: 1.1
Limit parameters for throttling. Since some limit combinations are illegal, limits should always be set in one transaction. All fields are optional. When setting limits, if a field is missing the current value is not changed.
Members:
iops-total: int
(optional)limit total I/O operations per second
iops-total-max: int
(optional)I/O operations burst
iops-total-max-length: int
(optional)length of the iops-total-max burst period, in seconds
It must only be set if iops-total-max
is set as well.
iops-read: int
(optional)limit read operations per second
iops-read-max: int
(optional)I/O operations read burst
iops-read-max-length: int
(optional)length of the iops-read-max burst period, in seconds
It must only be set if iops-read-max
is set as well.
iops-write: int
(optional)limit write operations per second
iops-write-max: int
(optional)I/O operations write burst
iops-write-max-length: int
(optional)length of the iops-write-max burst period, in seconds
It must only be set if iops-write-max
is set as well.
bps-total: int
(optional)limit total bytes per second
bps-total-max: int
(optional)total bytes burst
bps-total-max-length: int
(optional)length of the bps-total-max burst period, in seconds.
It must only be set if bps-total-max
is set as well.
bps-read: int
(optional)limit read bytes per second
bps-read-max: int
(optional)total bytes read burst
bps-read-max-length: int
(optional)length of the bps-read-max burst period, in seconds
It must only be set if bps-read-max
is set as well.
bps-write: int
(optional)limit write bytes per second
bps-write-max: int
(optional)total bytes write burst
bps-write-max-length: int
(optional)length of the bps-write-max burst period, in seconds
It must only be set if bps-write-max
is set as well.
iops-size: int
(optional)when limiting by iops max size of an I/O in bytes
Since: 2.11
Copy data from a backing file into a block device.
The block streaming operation is performed in the background until the entire backing file has been copied. This command returns immediately once streaming has started. The status of ongoing block streaming operations can be checked with query-block-jobs. The operation can be stopped before it has completed using the block-job-cancel command.
The node that receives the data is called the top image, can be located in any part of the chain (but always above the base image; see below) and can be specified using its device or node name. Earlier qemu versions only allowed ’device’ to name the top level node; presence of the ’base-node’ parameter during introspection can be used as a witness of the enhanced semantics of ’device’.
If a base file is specified then sectors are not copied from that base file and its backing chain. When streaming completes the image file will have the base file as its backing file. This can be used to stream a subset of the backing file chain instead of flattening the entire image.
On successful completion the image file is updated to drop the backing file and the BLOCK_JOB_COMPLETED event is emitted.
Arguments:
job-id: string
(optional)identifier for the newly-created block job. If omitted, the device name will be used. (Since 2.7)
device: string
the device or node name of the top image
base: string
(optional)the common backing file name.
It cannot be set if base-node
is also set.
base-node: string
(optional)the node name of the backing file.
It cannot be set if base
is also set. (Since 2.8)
backing-file: string
(optional)The backing file string to write into the top image. This filename is not validated.
If a pathname string is such that it cannot be resolved by QEMU, that means that subsequent QMP or HMP commands must use node-names for the image in question, as filename lookup methods will fail.
If not specified, QEMU will automatically determine the backing file string to use, or error out if there is no obvious choice. Care should be taken when specifying the string, to specify a valid filename or protocol. (Since 2.1)
speed: int
(optional)the maximum speed, in bytes per second
on-error: BlockdevOnError
(optional)the action to take on an error (default report). ’stop’ and ’enospc’ can only be used if the block device supports io-status (see BlockInfo). Since 1.3.
auto-finalize: boolean
(optional)When false, this job will wait in a PENDING state after it has
finished its work, waiting for block-job-finalize
before
making any block graph changes.
When true, this job will automatically
perform its abort or commit actions.
Defaults to true. (Since 3.1)
auto-dismiss: boolean
(optional)When false, this job will wait in a CONCLUDED state after it
has completely ceased all work, and awaits block-job-dismiss
.
When true, this job will automatically disappear from the query
list without user intervention.
Defaults to true. (Since 3.1)
Returns:
device
does not exist, DeviceNotFound.
Since: 1.1
Example:
-> { "execute": "block-stream", "arguments": { "device": "virtio0", "base": "/tmp/master.qcow2" } } <- { "return": {} }
Set maximum speed for a background block operation.
This command can only be issued when there is an active block job.
Throttling can be disabled by setting the speed to 0.
Arguments:
device: string
The job identifier. This used to be a device name (hence the name of the parameter), but since QEMU 2.7 it can have other values.
speed: int
the maximum speed, in bytes per second, or 0 for unlimited. Defaults to 0.
Returns:
Since: 1.1
Stop an active background block operation.
This command returns immediately after marking the active background block operation for cancellation. It is an error to call this command if no operation is in progress.
The operation will cancel as soon as possible and then emit the BLOCK_JOB_CANCELLED event. Before that happens the job is still visible when enumerated using query-block-jobs.
Note that if you issue ’block-job-cancel’ after ’drive-mirror’ has indicated (via the event BLOCK_JOB_READY) that the source and destination are synchronized, then the event triggered by this command changes to BLOCK_JOB_COMPLETED, to indicate that the mirroring has ended and the destination now has a point-in-time copy tied to the time of the cancellation.
For streaming, the image file retains its backing file unless the streaming operation happens to complete just as it is being cancelled. A new streaming operation can be started at a later time to finish copying all data from the backing file.
Arguments:
device: string
The job identifier. This used to be a device name (hence the name of the parameter), but since QEMU 2.7 it can have other values.
force: boolean
(optional)If true, and the job has already emitted the event BLOCK_JOB_READY, abandon the job immediately (even if it is paused) instead of waiting for the destination to complete its final synchronization (since 1.3)
Returns:
Since: 1.1
Pause an active background block operation.
This command returns immediately after marking the active background block operation for pausing. It is an error to call this command if no operation is in progress or if the job is already paused.
The operation will pause as soon as possible. No event is emitted when the operation is actually paused. Cancelling a paused job automatically resumes it.
Arguments:
device: string
The job identifier. This used to be a device name (hence the name of the parameter), but since QEMU 2.7 it can have other values.
Returns:
Since: 1.3
Resume an active background block operation.
This command returns immediately after resuming a paused background block operation. It is an error to call this command if no operation is in progress or if the job is not paused.
This command also clears the error status of the job.
Arguments:
device: string
The job identifier. This used to be a device name (hence the name of the parameter), but since QEMU 2.7 it can have other values.
Returns:
Since: 1.3
Manually trigger completion of an active background block operation. This is supported for drive mirroring, where it also switches the device to write to the target path only. The ability to complete is signaled with a BLOCK_JOB_READY event.
This command completes an active background block operation synchronously. The ordering of this command’s return with the BLOCK_JOB_COMPLETED event is not defined. Note that if an I/O error occurs during the processing of this command: 1) the command itself will fail; 2) the error will be processed according to the rerror/werror arguments that were specified when starting the operation.
A cancelled or paused job cannot be completed.
Arguments:
device: string
The job identifier. This used to be a device name (hence the name of the parameter), but since QEMU 2.7 it can have other values.
Returns:
Since: 1.3
For jobs that have already concluded, remove them from the block-job-query list. This command only needs to be run for jobs which were started with QEMU 2.12+ job lifetime management semantics.
This command will refuse to operate on any job that has not yet reached its terminal state, JOB_STATUS_CONCLUDED. For jobs that make use of the BLOCK_JOB_READY event, block-job-cancel or block-job-complete will still need to be used as appropriate.
Arguments:
id: string
The job identifier.
Returns: Nothing on success
Since: 2.12
Once a job that has manual=true reaches the pending state, it can be instructed to finalize any graph changes and do any necessary cleanup via this command. For jobs in a transaction, instructing one job to finalize will force ALL jobs in the transaction to finalize, so it is only necessary to instruct a single member job to finalize.
Arguments:
id: string
The job identifier.
Returns: Nothing on success
Since: 2.12
Determines how to handle discard requests.
Values:
ignore
Ignore the request
unmap
Forward as an unmap request
Since: 2.9
Describes the operation mode for the automatic conversion of plain zero writes by the OS to driver specific optimized zero write commands.
 This requires
also that BlockdevDiscardOptions
is set to unmap for this device.
Since: 2.1
Selects the AIO backend to handle I/O requests
Values:
threads
Use qemu’s thread pool
native
Use native AIO backend (only Linux and Windows)
io_uring
Use linux io_uring (since 5.0)
If: defined(CONFIG_LINUX_IO_URING)
Since: 2.9
Includes cache-related options for block devices
Members:
direct: boolean
(optional)enables use of O_DIRECT (bypass the host page cache; default: false)
no-flush: boolean
(optional)ignore any flush requests for the device (default: false)
Since: 2.9
Drivers that are supported in block device operations.

Members:
filename: string
path to the image file
pr-manager: string
(optional)the id for the object that will handle persistent reservations for this device (default: none, forward the commands via SG_IO; since 2.11)
aio: BlockdevAioOptions
(optional)AIO backend (default: threads) (since: 2.8)
locking: OnOffAuto
(optional)whether to enable file locking. If set to ’auto’, only enable when Open File Descriptor (OFD) locking API is available (default: auto, since 2.10)
drop-cache: boolean
(optional)invalidate page cache during live migration. This prevents
stale data on the migration destination with cache.direct=off.
Currently only supported on Linux hosts.
(default: on, since: 4.0)
If: defined(CONFIG_LINUX)
x-check-cache-dropped: boolean
(optional)whether to check that page cache was dropped on live migration. May cause noticeable delays if the image file is large, do not use in production. (default: off) (since: 3.0)
Features:
dynamic-auto-read-only
If present, enabled auto-read-only means that the driver will open the image read-only at first, dynamically reopen the image file read-write when the first writer is attached to the node and reopen read-only when the last writer is detached. This allows giving QEMU write permissions only on demand when an operation actually needs write access.
Since: 2.9
Driver specific block device options for the null backend.
Members:
size: int
(optional)size of the device in bytes.
latency-ns: int
(optional)emulated latency (in nanoseconds) in processing requests. Default to zero which completes requests immediately. (Since 2.4)
read-zeroes: boolean
(optional)if true, reads from the device produce zeroes; if false, the buffer is left unchanged. (default: false; since: 4.1)
Since: 2.9
Driver specific block device options for the NVMe backend.
Members:
device: string
PCI controller address of the NVMe device in format hhhh:bb:ss.f (host:bus:slot.function)
namespace: int
namespace number of the device, starting from 1.
Note that the PCI device
must have been unbound from any host
kernel driver before instructing QEMU to add the blockdev.
Since: 2.12
Driver specific block device options for the vvfat protocol.
Members:
dir: string
directory to be exported as FAT image
fat-type: int
(optional)FAT type: 12, 16 or 32
floppy: boolean
(optional)whether to export a floppy image (true) or partitioned hard disk (false; default)
label: string
(optional)set the volume label, limited to 11 bytes. FAT16 and FAT32 traditionally have some restrictions on labels, which are ignored by most operating systems. Defaults to "QEMU VVFAT". (since 2.4)
rw: boolean
(optional)whether to allow write operations (default: false)
Since: 2.9
Driver specific block device options for image format that have no option besides their data source.
Members:
file: BlockdevRef
reference to or definition of the data source block device
Since: 2.9
Driver specific block device options for LUKS.
Members:
key-secret: string
(optional)the ID of a QCryptoSecret object providing the decryption key (since 2.6). Mandatory except when doing a metadata-only probe of the image.
BlockdevOptionsGenericFormat
Since: 2.9
Driver specific block device options for image format that have no option besides their data source and an optional backing file.
Members:
backing: BlockdevRefOrNull
(optional)reference to or definition of the backing file block device, null disables the backing file entirely. Defaults to the backing file stored the image file.
BlockdevOptionsGenericFormat
Since: 2.9
General overlap check modes.
Values:
none
Do not perform any checks
constant
Perform only checks which can be done in constant time and without reading anything from disk
cached
Perform only checks which can be done without reading anything from disk
all
Perform all available overlap checks
Since: 2.9
Structure of flags for each metadata structure. Setting a field to ’true’ makes qemu guard that structure against unintended overwriting. The default value is chosen according to the template given.
Members:
template: Qcow2OverlapCheckMode
(optional)Specifies a template mode which can be adjusted using the other flags, defaults to ’cached’
bitmap-directory: boolean
(optional)since 3.0
main-header: boolean
(optional)Not documented
active-l1: boolean
(optional)Not documented
active-l2: boolean
(optional)Not documented
refcount-table: boolean
(optional)Not documented
refcount-block: boolean
(optional)Not documented
snapshot-table: boolean
(optional)Not documented
inactive-l1: boolean
(optional)Not documented
inactive-l2: boolean
(optional)Not documented
Since: 2.9
Specifies which metadata structures should be guarded against unintended overwriting.
Members:
flags: Qcow2OverlapCheckFlags
set of flags for separate specification of each metadata structure type
mode: Qcow2OverlapCheckMode
named mode which chooses a specific set of flags
Since: 2.9
Values:
aes
AES-CBC with plain64 initialization vectors
Since: 2.10
Members:
format: BlockdevQcowEncryptionFormat
Not documented
QCryptoBlockOptionsQCow
when format
is "aes"Since: 2.10
Driver specific block device options for qcow.
Members:
encrypt: BlockdevQcowEncryption
(optional)Image decryption options. Mandatory for encrypted images, except when doing a metadata-only probe of the image.
BlockdevOptionsGenericCOWFormat
Since: 2.10
Values:
aes
AES-CBC with plain64 initialization vectors
luks
Not documented
Since: 2.10
Members:
format: BlockdevQcow2EncryptionFormat
Not documented
QCryptoBlockOptionsQCow
when format
is "aes"QCryptoBlockOptionsLUKS
when format
is "luks"Since: 2.10
Driver specific block device options for qcow2.
Members:
lazy-refcounts: boolean
(optional)whether to enable the lazy refcounts feature (default is taken from the image file)
pass-discard-request: boolean
(optional)whether discard requests to the qcow2 device should be forwarded to the data source
pass-discard-snapshot: boolean
(optional)whether discard requests for the data source should be issued when a snapshot operation (e.g. deleting a snapshot) frees clusters in the qcow2 file
pass-discard-other: boolean
(optional)whether discard requests for the data source should be issued on other occasions where a cluster gets freed
overlap-check: Qcow2OverlapChecks
(optional)which overlap checks to perform for writes to the image, defaults to ’cached’ (since 2.2)
cache-size: int
(optional)the maximum total size of the L2 table and refcount block caches in bytes (since 2.2)
l2-cache-size: int
(optional)the maximum size of the L2 table cache in bytes (since 2.2)
l2-cache-entry-size: int
(optional)the size of each entry in the L2 cache in bytes. It must be a power of two between 512 and the cluster size. The default value is the cluster size (since 2.12)
refcount-cache-size: int
(optional)the maximum size of the refcount block cache in bytes (since 2.2)
cache-clean-interval: int
(optional)clean unused entries in the L2 and refcount caches. The interval is in seconds. The default value is 600 on supporting platforms, and 0 on other platforms. 0 disables this feature. (since 2.5)
encrypt: BlockdevQcow2Encryption
(optional)Image decryption options. Mandatory for encrypted images, except when doing a metadata-only probe of the image. (since 2.10)
data-file: BlockdevRef
(optional)reference to or definition of the external data file. This may only be specified for images that require an external data file. If it is not specified for such an image, the data file name is loaded from the image file. (since 4.0)
BlockdevOptionsGenericCOWFormat
Since: 2.9
Values:
none
Don’t check the host key at all
hash
Compare the host key with a given hash
known_hosts
Check the host key against the known_hosts file
Since: 2.12
Values:
md5
The given hash is an md5 hash
sha1
The given hash is an sha1 hash
Since: 2.12
Members:
type: SshHostKeyCheckHashType
The hash algorithm used for the hash
hash: string
The expected hash value
Since: 2.12
Members:
mode: SshHostKeyCheckMode
Not documented
SshHostKeyHash
when mode
is "hash"Since: 2.12
Members:
server: InetSocketAddress
host address
path: string
path to the image on the host
user: string
(optional)user as which to connect, defaults to current local user name
host-key-check: SshHostKeyCheck
(optional)Defines how and what to check the host key against (default: known_hosts)
Since: 2.9
Trigger events supported by blkdebug.
Values:
l1_shrink_write_table
write zeros to the l1 table to shrink image. (since 2.11)
l1_shrink_free_l2_clusters
discard the l2 tables. (since 2.11)
cor_write
a write due to copy-on-read (since 2.11)
cluster_alloc_space
an allocation of file space for a cluster (since 4.1)
none
triggers once at creation of the blkdebug node (since 4.1)
l1_update
Not documented
l1_grow_alloc_table
Not documented
l1_grow_write_table
Not documented
l1_grow_activate_table
Not documented
l2_load
Not documented
l2_update
Not documented
l2_update_compressed
Not documented
l2_alloc_cow_read
Not documented
l2_alloc_write
Not documented
read_aio
Not documented
read_backing_aio
Not documented
read_compressed
Not documented
write_aio
Not documented
write_compressed
Not documented
vmstate_load
Not documented
vmstate_save
Not documented
cow_read
Not documented
cow_write
Not documented
reftable_load
Not documented
reftable_grow
Not documented
reftable_update
Not documented
refblock_load
Not documented
refblock_update
Not documented
refblock_update_part
Not documented
refblock_alloc
Not documented
refblock_alloc_hookup
Not documented
refblock_alloc_write
Not documented
refblock_alloc_write_blocks
Not documented
refblock_alloc_write_table
Not documented
refblock_alloc_switch_table
Not documented
cluster_alloc
Not documented
cluster_alloc_bytes
Not documented
cluster_free
Not documented
flush_to_os
Not documented
flush_to_disk
Not documented
pwritev_rmw_head
Not documented
pwritev_rmw_after_head
Not documented
pwritev_rmw_tail
Not documented
pwritev_rmw_after_tail
Not documented
pwritev
Not documented
pwritev_zero
Not documented
pwritev_done
Not documented
empty_image_prepare
Not documented
Since: 2.9
Kinds of I/O that blkdebug can inject errors in.
Values:
read
.bdrv_co_preadv()
write
.bdrv_co_pwritev()
write-zeroes
.bdrv_co_pwrite_zeroes()
discard
.bdrv_co_pdiscard()
flush
.bdrv_co_flush_to_disk()
block-status
.bdrv_co_block_status()
Since: 4.1
Describes a single error injection for blkdebug.
Members:
event: BlkdebugEvent
trigger event
state: int
(optional)the state identifier blkdebug needs to be in to actually trigger the event; defaults to "any"
iotype: BlkdebugIOType
(optional)the type of I/O operations on which this error should be injected; defaults to "all read, write, write-zeroes, discard, and flush operations" (since: 4.1)
errno: int
(optional)error identifier (errno) to be returned; defaults to EIO
sector: int
(optional)specifies the sector index which has to be affected in order to actually trigger the event; defaults to "any sector"
once: boolean
(optional)disables further events after this one has been triggered; defaults to false
immediately: boolean
(optional)fail immediately; defaults to false
Since: 2.9
Describes a single state-change event for blkdebug.
Members:
event: BlkdebugEvent
trigger event
state: int
(optional)the current state identifier blkdebug needs to be in; defaults to "any"
new_state: int
the state identifier blkdebug is supposed to assume if this event is triggered
Since: 2.9
Driver specific block device options for blkdebug.
Members:
image: BlockdevRef
underlying raw block device (or image file)
config: string
(optional)filename of the configuration file
align: int
(optional)required alignment for requests in bytes, must be positive power of 2, or 0 for default
max-transfer: int
(optional)maximum size for I/O transfers in bytes, must be
positive multiple of align
and of the underlying
file’s request alignment (but need not be a power of
2), or 0 for default (since 2.10)
opt-write-zero: int
(optional)preferred alignment for write zero requests in bytes,
must be positive multiple of align
and of the
underlying file’s request alignment (but need not be a
power of 2), or 0 for default (since 2.10)
max-write-zero: int
(optional)maximum size for write zero requests in bytes, must be
positive multiple of align
, of opt-write-zero
, and of
the underlying file’s request alignment (but need not
be a power of 2), or 0 for default (since 2.10)
opt-discard: int
(optional)preferred alignment for discard requests in bytes, must
be positive multiple of align
and of the underlying
file’s request alignment (but need not be a power of
2), or 0 for default (since 2.10)
max-discard: int
(optional)maximum size for discard requests in bytes, must be
positive multiple of align
, of opt-discard
, and of
the underlying file’s request alignment (but need not
be a power of 2), or 0 for default (since 2.10)
inject-error: array of BlkdebugInjectErrorOptions
(optional)array of error injection descriptions
set-state: array of BlkdebugSetStateOptions
(optional)array of state-change descriptions
take-child-perms: array of BlockPermission
(optional)Permissions to take on image
in addition to what
is necessary anyway (which depends on how the
blkdebug node is used). Defaults to none.
(since 5.0)
unshare-child-perms: array of BlockPermission
(optional)Permissions not to share on image
in addition
to what cannot be shared anyway (which depends
on how the blkdebug node is used). Defaults
to none. (since 5.0)
Since: 2.9
Driver specific block device options for blklogwrites.
Members:
file: BlockdevRef
block device
log: BlockdevRef
block device used to log writes to file
log-sector-size: int
(optional)sector size used in logging writes to file
, determines
granularity of offsets and sizes of writes (default: 512)
log-append: boolean
(optional)append to an existing log (default: false)
log-super-update-interval: int
(optional)interval of write requests after which the log super block is updated to disk (default: 4096)
Since: 3.0
Driver specific block device options for blkverify.
Members:
test: BlockdevRef
block device to be tested
raw: BlockdevRef
raw image used for verification
Since: 2.9
Driver specific block device options for blkreplay.
Members:
image: BlockdevRef
disk image which should be controlled with blkreplay
Since: 4.2
An enumeration of quorum read patterns.
Values:
quorum
read all the children and do a quorum vote on reads
fifo
read only from the first child that has not failed
Since: 2.9
Driver specific block device options for Quorum
Members:
blkverify: boolean
(optional)true if the driver must print content mismatch set to false by default
children: array of BlockdevRef
the children block devices to use
vote-threshold: int
the vote limit under which a read will fail
rewrite-corrupted: boolean
(optional)rewrite corrupted data when quorum is reached (Since 2.1)
read-pattern: QuorumReadPattern
(optional)choose read pattern and set to quorum by default (Since 2.2)
Since: 2.9
Driver specific block device options for Gluster
Members:
volume: string
name of gluster volume where VM image resides
path: string
absolute path to image file in gluster volume
server: array of SocketAddress
gluster servers description
debug: int
(optional)libgfapi log level (default ’4’ which is Error) (Since 2.8)
logfile: string
(optional)libgfapi log file (default /dev/stderr) (Since 2.8)
Since: 2.9
An enumeration of libiscsi transport types
Values:
tcp
Not documented
iser
Not documented
Since: 2.9
An enumeration of header digests supported by libiscsi
Values:
crc32c
Not documented
none
Not documented
crc32c-none
Not documented
none-crc32c
Not documented
Since: 2.9
Members:
transport: IscsiTransport
The iscsi transport type
portal: string
The address of the iscsi portal
target: string
The target iqn name
lun: int
(optional)LUN to connect to. Defaults to 0.
user: string
(optional)User name to log in with. If omitted, no CHAP authentication is performed.
password-secret: string
(optional)The ID of a QCryptoSecret object providing
the password for the login. This option is required if
user
is specified.
initiator-name: string
(optional)The iqn name we want to identify to the target as. If this option is not specified, an initiator name is generated automatically.
header-digest: IscsiHeaderDigest
(optional)The desired header digest. Defaults to none-crc32c.
timeout: int
(optional)Timeout in seconds after which a request will timeout. 0 means no timeout and is the default.
Driver specific block device options for iscsi
Since: 2.9
Values:
cephx
Not documented
none
Not documented
Since: 3.0
Members:
pool: string
Ceph pool name.
namespace: string
(optional)Rados namespace name in the Ceph pool. (Since 5.0)
image: string
Image name in the Ceph pool.
conf: string
(optional)path to Ceph configuration file. Values in the configuration file will be overridden by options specified via QAPI.
snapshot: string
(optional)Ceph snapshot name.
user: string
(optional)Ceph id name.
auth-client-required: array of RbdAuthMode
(optional)Acceptable authentication modes. This maps to Ceph configuration option "auth_client_required". (Since 3.0)
key-secret: string
(optional)ID of a QCryptoSecret object providing a key for cephx authentication. This maps to Ceph configuration option "key". (Since 3.0)
server: array of InetSocketAddressBase
(optional)Monitor host address and port. This maps to the "mon_host" Ceph option.
Since: 2.9
Driver specific block device options for sheepdog
Members:
vdi: string
Virtual disk image name
server: SocketAddress
The Sheepdog server to connect to
snap-id: int
(optional)Snapshot ID
tag: string
(optional)Snapshot tag name
Only one of snap-id
and tag
may be present.
Since: 2.9
An enumeration of replication modes.
Values:
primary
Primary mode, the vm’s state will be sent to secondary QEMU.
secondary
Secondary mode, receive the vm’s state from primary QEMU.
Since: 2.9
If: defined(CONFIG_REPLICATION)
Driver specific block device options for replication
Members:
mode: ReplicationMode
the replication mode
top-id: string
(optional)In secondary mode, node name or device ID of the root node who owns the replication node chain. Must not be given in primary mode.
BlockdevOptionsGenericFormat
Since: 2.9
If: defined(CONFIG_REPLICATION)
An enumeration of NFS transport types
Values:
inet
TCP transport
Since: 2.9
Captures the address of the socket
Members:
type: NFSTransport
transport type used for NFS (only TCP supported)
host: string
host address for NFS server
Since: 2.9
Driver specific block device option for NFS
Members:
server: NFSServer
host address
path: string
path of the image on the host
user: int
(optional)UID value to use when talking to the server (defaults to 65534 on Windows and getuid() on unix)
group: int
(optional)GID value to use when talking to the server (defaults to 65534 on Windows and getgid() in unix)
tcp-syn-count: int
(optional)number of SYNs during the session establishment (defaults to libnfs default)
readahead-size: int
(optional)set the readahead size in bytes (defaults to libnfs default)
page-cache-size: int
(optional)set the pagecache size in bytes (defaults to libnfs default)
debug: int
(optional)set the NFS debug level (max 2) (defaults to libnfs default)
Since: 2.9
Driver specific block device options shared by all protocols supported by the curl backend.
Members:
url: string
URL of the image file
readahead: int
(optional)Size of the read-ahead cache; must be a multiple of 512 (defaults to 256 kB)
timeout: int
(optional)Timeout for connections, in seconds (defaults to 5)
username: string
(optional)Username for authentication (defaults to none)
password-secret: string
(optional)ID of a QCryptoSecret object providing a password for authentication (defaults to no password)
proxy-username: string
(optional)Username for proxy authentication (defaults to none)
proxy-password-secret: string
(optional)ID of a QCryptoSecret object providing a password for proxy authentication (defaults to no password)
Since: 2.9
Driver specific block device options for HTTP connections over the curl backend. URLs must start with "http://".
Members:
cookie: string
(optional)List of cookies to set; format is "name1=content1; name2=content2;" as explained by CURLOPT_COOKIE(3). Defaults to no cookies.
cookie-secret: string
(optional)ID of a QCryptoSecret object providing the cookie data in a
secure way. See cookie
for the format. (since 2.10)
BlockdevOptionsCurlBase
Since: 2.9
Driver specific block device options for HTTPS connections over the curl backend. URLs must start with "https://".
Members:
cookie: string
(optional)List of cookies to set; format is "name1=content1; name2=content2;" as explained by CURLOPT_COOKIE(3). Defaults to no cookies.
sslverify: boolean
(optional)Whether to verify the SSL certificate’s validity (defaults to true)
cookie-secret: string
(optional)ID of a QCryptoSecret object providing the cookie data in a
secure way. See cookie
for the format. (since 2.10)
BlockdevOptionsCurlBase
Since: 2.9
Driver specific block device options for FTP connections over the curl backend. URLs must start with "ftp://".
Members:
BlockdevOptionsCurlBase
Since: 2.9
Driver specific block device options for FTPS connections over the curl backend. URLs must start with "ftps://".
Members:
sslverify: boolean
(optional)Whether to verify the SSL certificate’s validity (defaults to true)
BlockdevOptionsCurlBase
Since: 2.9
Driver specific block device options for NBD.
Members:
server: SocketAddress
NBD server address
export: string
(optional)export name
tls-creds: string
(optional)TLS credentials ID
x-dirty-bitmap: string
(optional)A "qemu:dirty-bitmap:NAME" string to query in place of traditional "base:allocation" block status (see NBD_OPT_LIST_META_CONTEXT in the NBD protocol) (since 3.0)
reconnect-delay: int
(optional)On an unexpected disconnect, the nbd client tries to
connect again until succeeding or encountering a serious
error. During the first reconnect-delay
seconds, all
requests are paused and will be rerun on a successful
reconnect. After that time, any delayed requests and all
future requests before a successful reconnect will
immediately fail. Default 0 (Since 4.2)
Since: 2.9
Driver specific block device options for the raw driver.
Members:
offset: int
(optional)position where the block device starts
size: int
(optional)the assumed size of the device
BlockdevOptionsGenericFormat
Since: 2.9
Driver specific block device options for the throttle driver
Members:
throttle-group: string
the name of the throttle-group object to use. It must already exist.
file: BlockdevRef
reference to or definition of the data source block device
Since: 2.11
Options for creating a block device. Many options are available for all block devices, independent of the block driver:
Members:
driver: BlockdevDriver
block driver name
node-name: string
(optional)the node name of the new node (Since 2.0). This option is required on the top level of blockdev-add. Valid node names start with an alphabetic character and may contain only alphanumeric characters, ’-’, ’.’ and ’_’. Their maximum length is 31 characters.
discard: BlockdevDiscardOptions
(optional)discard-related options (default: ignore)
cache: BlockdevCacheOptions
(optional)cache-related options
read-only: boolean
(optional)whether the block device should be read-only (default: false). Note that some block drivers support only read-only access, either generally or in certain configurations. In this case, the default value does not work and the option must be specified explicitly.
auto-read-only: boolean
(optional)if true and read-only
is false, QEMU may automatically
decide not to open the image read-write as requested, but
fall back to read-only instead (and switch between the modes
later), e.g. depending on whether the image file is writable
or whether a writing user is attached to the node
(default: false, since 3.1)
detect-zeroes: BlockdevDetectZeroesOptions
(optional)detect and optimize zero writes (Since 2.1) (default: off)
force-share: boolean
(optional)force share all permission on added nodes. Requires read-only=true. (Since 2.10)
BlockdevOptionsBlkdebug
when driver
is "blkdebug"BlockdevOptionsBlklogwrites
when driver
is "blklogwrites"BlockdevOptionsBlkverify
when driver
is "blkverify"BlockdevOptionsBlkreplay
when driver
is "blkreplay"BlockdevOptionsGenericFormat
when driver
is "bochs"BlockdevOptionsGenericFormat
when driver
is "cloop"BlockdevOptionsGenericFormat
when driver
is "compress"BlockdevOptionsGenericFormat
when driver
is "copy-on-read"BlockdevOptionsGenericFormat
when driver
is "dmg"BlockdevOptionsFile
when driver
is "file"BlockdevOptionsCurlFtp
when driver
is "ftp"BlockdevOptionsCurlFtps
when driver
is "ftps"BlockdevOptionsGluster
when driver
is "gluster"BlockdevOptionsFile
when driver
is "host_cdrom"BlockdevOptionsFile
when driver
is "host_device"BlockdevOptionsCurlHttp
when driver
is "http"BlockdevOptionsCurlHttps
when driver
is "https"BlockdevOptionsIscsi
when driver
is "iscsi"BlockdevOptionsLUKS
when driver
is "luks"BlockdevOptionsNbd
when driver
is "nbd"BlockdevOptionsNfs
when driver
is "nfs"BlockdevOptionsNull
when driver
is "null-aio"BlockdevOptionsNull
when driver
is "null-co"BlockdevOptionsNVMe
when driver
is "nvme"BlockdevOptionsGenericFormat
when driver
is "parallels"BlockdevOptionsQcow2
when driver
is "qcow2"BlockdevOptionsQcow
when driver
is "qcow"BlockdevOptionsGenericCOWFormat
when driver
is "qed"BlockdevOptionsQuorum
when driver
is "quorum"BlockdevOptionsRaw
when driver
is "raw"BlockdevOptionsRbd
when driver
is "rbd"BlockdevOptionsReplication
when driver
is "replication" (If: defined(CONFIG_REPLICATION)
)BlockdevOptionsSheepdog
when driver
is "sheepdog"BlockdevOptionsSsh
when driver
is "ssh"BlockdevOptionsThrottle
when driver
is "throttle"BlockdevOptionsGenericFormat
when driver
is "vdi"BlockdevOptionsGenericFormat
when driver
is "vhdx"BlockdevOptionsGenericCOWFormat
when driver
is "vmdk"BlockdevOptionsGenericFormat
when driver
is "vpc"BlockdevOptionsVVFAT
when driver
is "vvfat"Remaining options are determined by the block driver.
Since: 2.9
Reference to a block device.
Members:
definition: BlockdevOptions
defines a new block device inline
reference: string
references the ID of an existing block device
Since: 2.9
Reference to a block device.
Members:
definition: BlockdevOptions
defines a new block device inline
reference: string
references the ID of an existing block device. An empty string means that no block device should be referenced. Deprecated; use null instead.
null: null
No block device should be referenced (since 2.10)
Since: 2.9
Creates a new block device. If the id
option is given at the top level, a
BlockBackend will be created; otherwise, node-name
is mandatory at the top
level and no BlockBackend will be created.
Arguments: the members of BlockdevOptions
Since: 2.9
Example:
1. -> { "execute": "blockdev-add", "arguments": { "driver": "qcow2", "node-name": "test1", "file": { "driver": "file", "filename": "test.qcow2" } } } <- { "return": {} } 2. -> { "execute": "blockdev-add", "arguments": { "driver": "qcow2", "node-name": "node0", "discard": "unmap", "cache": { "direct": true }, "file": { "driver": "file", "filename": "/tmp/test.qcow2" }, "backing": { "driver": "raw", "file": { "driver": "file", "filename": "/dev/fdset/4" } } } } <- { "return": {} }
Reopens a block device using the given set of options. Any option not specified will be reset to its default value regardless of its previous status. If an option cannot be changed or a particular driver does not support reopening then the command will return an error.
The top-level node-name
option (from BlockdevOptions) must be
specified and is used to select the block device to be reopened.
Other node-name
options must be either omitted or set to the
current name of the appropriate node. This command won’t change any
node name and any attempt to do it will result in an error.
In the case of options that refer to child nodes, the behavior of this command depends on the value:
1) A set of options (BlockdevOptions): the child is reopened with the specified set of options.
2) A reference to the current child: the child is reopened using its existing set of options.
3) A reference to a different node: the current child is replaced with the specified one.
4) NULL: the current child (if any) is detached.
Options (1) and (2) are supported in all cases, but at the moment
only backing
allows replacing or detaching an existing child.
Unlike with blockdev-add, the backing
option must always be present
unless the node being reopened does not have a backing file and its
image does not have a default backing file name as part of its
metadata.
Arguments: the members of BlockdevOptions
Since: 4.0
Deletes a block device that has been added using blockdev-add. The command will fail if the node is attached to a device or is otherwise being used.
Arguments:
node-name: string
Name of the graph node to delete.
Since: 2.9
Example:
-> { "execute": "blockdev-add", "arguments": { "driver": "qcow2", "node-name": "node0", "file": { "driver": "file", "filename": "test.qcow2" } } } <- { "return": {} } -> { "execute": "blockdev-del", "arguments": { "node-name": "node0" } } <- { "return": {} }
Driver specific image creation options for file.
Members:
filename: string
Filename for the new image file
size: int
Size of the virtual disk in bytes
preallocation: PreallocMode
(optional)Preallocation mode for the new image (default: off; allowed values: off, falloc (if defined CONFIG_POSIX_FALLOCATE), full (if defined CONFIG_POSIX))
nocow: boolean
(optional)Turn off copy-on-write (valid only on btrfs; default: off)
extent-size-hint: int
(optional)Extent size hint to add to the image file; 0 for not adding an extent size hint (default: 1 MB, since 5.1)
Since: 2.12
Driver specific image creation options for gluster.
Members:
location: BlockdevOptionsGluster
Where to store the new image file
size: int
Size of the virtual disk in bytes
preallocation: PreallocMode
(optional)Preallocation mode for the new image (default: off; allowed values: off, falloc (if defined CONFIG_GLUSTERFS_FALLOCATE), full (if defined CONFIG_GLUSTERFS_ZEROFILL))
Since: 2.12
Driver specific image creation options for LUKS.
Members:
file: BlockdevRef
Node to create the image format on
size: int
Size of the virtual disk in bytes
preallocation: PreallocMode
(optional)Preallocation mode for the new image (since: 4.2) (default: off; allowed values: off, metadata, falloc, full)
QCryptoBlockCreateOptionsLUKS
Since: 2.12
Driver specific image creation options for NFS.
Members:
location: BlockdevOptionsNfs
Where to store the new image file
size: int
Size of the virtual disk in bytes
Since: 2.12
Driver specific image creation options for parallels.
Members:
file: BlockdevRef
Node to create the image format on
size: int
Size of the virtual disk in bytes
cluster-size: int
(optional)Cluster size in bytes (default: 1 MB)
Since: 2.12
Driver specific image creation options for qcow.
Members:
file: BlockdevRef
Node to create the image format on
size: int
Size of the virtual disk in bytes
backing-file: string
(optional)File name of the backing file if a backing file should be used
encrypt: QCryptoBlockCreateOptions
(optional)Encryption options if the image should be encrypted
Since: 2.12
Values:
v2
The original QCOW2 format as introduced in qemu 0.10 (version 2)
v3
The extended QCOW2 format as introduced in qemu 1.1 (version 3)
Since: 2.12
Compression type used in qcow2 image file
Values:
zlib
zlib compression, see <http://zlib.net/>
zstd
zstd compression, see <http://github.com/facebook/zstd>
If: defined(CONFIG_ZSTD)
Since: 5.1
Driver specific image creation options for qcow2.
Members:
file: BlockdevRef
Node to create the image format on
data-file: BlockdevRef
(optional)Node to use as an external data file in which all guest data is stored so that only metadata remains in the qcow2 file (since: 4.0)
data-file-raw: boolean
(optional)True if the external data file must stay valid as a standalone (read-only) raw image without looking at qcow2 metadata (default: false; since: 4.0)
size: int
Size of the virtual disk in bytes
version: BlockdevQcow2Version
(optional)Compatibility level (default: v3)
backing-file: string
(optional)File name of the backing file if a backing file should be used
backing-fmt: BlockdevDriver
(optional)Name of the block driver to use for the backing file
encrypt: QCryptoBlockCreateOptions
(optional)Encryption options if the image should be encrypted
cluster-size: int
(optional)qcow2 cluster size in bytes (default: 65536)
preallocation: PreallocMode
(optional)Preallocation mode for the new image (default: off; allowed values: off, falloc, full, metadata)
lazy-refcounts: boolean
(optional)True if refcounts may be updated lazily (default: off)
refcount-bits: int
(optional)Width of reference counts in bits (default: 16)
compression-type: Qcow2CompressionType
(optional)The image cluster compression method (default: zlib, since 5.1)
Since: 2.12
Driver specific image creation options for qed.
Members:
file: BlockdevRef
Node to create the image format on
size: int
Size of the virtual disk in bytes
backing-file: string
(optional)File name of the backing file if a backing file should be used
backing-fmt: BlockdevDriver
(optional)Name of the block driver to use for the backing file
cluster-size: int
(optional)Cluster size in bytes (default: 65536)
table-size: int
(optional)L1/L2 table size (in clusters)
Since: 2.12
Driver specific image creation options for rbd/Ceph.
Members:
location: BlockdevOptionsRbd
Where to store the new image file. This location cannot point to a snapshot.
size: int
Size of the virtual disk in bytes
cluster-size: int
(optional)RBD object size
Since: 2.12
Subformat options for VMDK images
Values:
monolithicSparse
Single file image with sparse cluster allocation
monolithicFlat
Single flat data image and a descriptor file
twoGbMaxExtentSparse
Data is split into 2GB (per virtual LBA) sparse extent files, in addition to a descriptor file
twoGbMaxExtentFlat
Data is split into 2GB (per virtual LBA) flat extent files, in addition to a descriptor file
streamOptimized
Single file image sparse cluster allocation, optimized for streaming over network.
Since: 4.0
Adapter type info for VMDK images
Values:
ide
Not documented
buslogic
Not documented
lsilogic
Not documented
legacyESX
Not documented
Since: 4.0
Driver specific image creation options for VMDK.
Members:
file: BlockdevRef
Where to store the new image file. This refers to the image file for monolithcSparse and streamOptimized format, or the descriptor file for other formats.
size: int
Size of the virtual disk in bytes
extents: array of BlockdevRef
(optional)Where to store the data extents. Required for monolithcFlat, twoGbMaxExtentSparse and twoGbMaxExtentFlat formats. For monolithicFlat, only one entry is required; for twoGbMaxExtent* formats, the number of entries required is calculated as extent_number = virtual_size / 2GB. Providing more extents than will be used is an error.
subformat: BlockdevVmdkSubformat
(optional)The subformat of the VMDK image. Default: "monolithicSparse".
backing-file: string
(optional)The path of backing file. Default: no backing file is used.
adapter-type: BlockdevVmdkAdapterType
(optional)The adapter type used to fill in the descriptor. Default: ide.
hwversion: string
(optional)Hardware version. The meaningful options are "4" or "6". Default: "4".
zeroed-grain: boolean
(optional)Whether to enable zeroed-grain feature for sparse subformats. Default: false.
Since: 4.0
Values:
full
Create a fully replicated vdi with x copies
erasure-coded
Create an erasure coded vdi with x data strips and y parity strips
Since: 2.12
Members:
copies: int
Number of copies to use (between 1 and 31)
Since: 2.12
Members:
data-strips: int
Number of data strips to use (one of {2,4,8,16})
parity-strips: int
Number of parity strips to use (between 1 and 15)
Since: 2.12
Members: