Virsh blockcommit

virsh blockcommit domain path [bandwidth] [--bytes] [base] [--shallow] [top] [--delete] [--keep-relative] [--wait [--async] [--verbose]] [--timeout seconds] [--active] [{--pivot | --keep-overlay}]

Requires at least QEMU 2.1 and libvirt-1.2.9 (2014).

Review your security_driver configuration in /ect/libvirt/qemu.conf. You may need to change it to none to allow virsh blockcommit

security_driver = "none"

Options:

--active to trigger a two-phase active commit

--pivot making base the new active image and invalidating top

--wait

--verbose

path, path specifies fully-qualified path of the disk; it corresponds to a unique target name (<target dev='name'/>) or source file (<source file='name'/>) for one of the disk devices attached to domain (see also domblklist for listing these names). Bandwidth specifies copying bandwidth limit in MiB/s, although for qemu, it may be non-zero only for an online domain

Examples

virsh blockcommit MY_DOMAIN_NAME [hdc|vda|xxx] --active
Active Block Commit started

virsh blockcommit MY_DOMAIN_NAME vda --active --pivot
Successfully pivoted

virsh blockcommit MY_DOMAIN_NAME /path/to/libvirt/MY_DOMAIN_NAME_DISK --active --pivot
Successfully pivoted

virsh blockcommit MY_DOMAIN_NAME vda --active --pivot
Commit aborted

virsh blockcommit MY_DOMAIN_NAME vda --active --pivot --wait --verbose
Block commit: [ 22 %]
Successfully pivoted

Use: virsh domblklist --details to find your block name.

Examples with errors

virsh blockcommit MY_DOMAIN_NAME 
error: command 'blockcommit' requires <path> option

virsh blockcommit MY_DOMAIN_NAME hda --active --pivot
error: invalid argument: top '/path/to/libvirt/MY_DOMAIN_NAME.qcow2' in chain for 'hda' has no backing file

virsh blockcommit stable-vm-1 /path/to/libvirt/MY_DOMAIN_NAME_DISK --active --pivot
error: block copy still active: disk 'vda' already in active block job

virsh blockcommit MY_DOMAIN_NAME hdc --active --pivot
error: block copy still active: disk 'hdc' already in active block job
Execute:
virsh blockjob MY_DOMAIN_NAME hdc --abort
(no output)
virsh blockjob MY_DOMAIN_NAME vda --info
No current block job for vda

Journalctl errors

Feb 04 16:29:52 SERVER libvirtd[14189]: 2019-11-21 15:08:13.035+0000: 14192: error : qemuDomainBlockCommit:17568 : invalid argument: top '/path/to/file/VM_NAME.qcow2' in chain for 'hda' has no backing file

Feb 04 16:29:52 SERVER libvirtd[14974]: 2020-02-04 12:29:52.421+0000: 14977: error : qemuDomainBlockCommit:17555 : invalid argument: commit of 'hdc' active layer requires active flag

Activities

• Create a KVM Live backup using virsh snapshot-create-as and virsh blockcommit
• Read https://www.redhat.com/archives/libvirt-users/2015-September/msg00042.html from Eric Blake (Red Hat)

Related terms

• virsh blockjob MY_DOMAIN_NAME vda --info
• virsh blockpull
• virsh snapshot-create-as and --quiesce option in virsh snapshot-create-as
• virsh domblklist

• KVM backup.sh
• virsh domblklist MY_DOMAIN_NAME
• virsh snapshot-list MY_DOMAIN_NAME

See also

• virsh blockcopy, virsh blockjob, virsh blockcommit, virsh domblklist, virsh blockresize, virsh blockpull
• virsh console
• virsh: Storage information, Connecting, Operations, Memory, Snapshots, Networking, CPU, release notes, virsh nodedev-list
• libvirtd: systemctl status libvirtd, systemctl status libvirt-guests, Libvirt release notes, logs, libvirtd.conf, /etc/libvirt/, /var/log/libvirt/

https://wiki.libvirt.org/page/Live-disk-backup-with-active-blockcommit

https://github.com/milkey-mouse/backup-vm/issues/17#issuecomment-547843000