Rapporto Tecnico, Anno 8, n° 44 settembre 2013

To mount it at boot:
# blkid
...
/dev/mapper/iscsi2-backup: UUID="0a413f6c-50cd-45c7-ba1c-0a413f6c1ac6" TYPE="ext4"
# nano -w /etc/fstab
+ UUID=0a413f6c-50cd-45c7-ba1c-0a413f6c1ac6
defaults,auto,_netdev
0
0

/var/lib/libvirt/backup

ext4

To take a live backup of VM tubu1-clone using LVM snapshot:
# ./virt-backup.pl --dump --vm=tubu1-clone --state --debug
Connecting to libvirt daemon using qemu:///system as URI
Checking tubu1-clone status
Running dump routine for tubu1-clone
Locking tubu1-clone
Saving XML description for tubu1-clone to /var/lib/libvirt/backup/tubu1-clone/tubu1-clone.xml
tubu1-clone is running, saving state....
tubu1-clone state saved as /var/lib/libvirt/backup/tubu1-clone/tubu1-clone.state
Analysing disk /dev/iscsi2/tubu1-clone connected on tubu1-clone as vda
Running: /sbin/lvcreate -c 512 -p r -s -n /dev/iscsi2/tubu1-clone_1344612236 -L 5G
/dev/iscsi2/tubu1-clone > /dev/null 2>&1
/dev/iscsi2/tubu1-clone seems to be a valid logical volume (LVM), a snapshot has been taken as
/dev/iscsi2/tubu1-clone_1344612236
Adding /dev/iscsi2/tubu1-clone_1344612236 to the list of disks to be backed up
The following disks will be dumped:
Source: /dev/iscsi2/tubu1-clone_1344612236
clone_vda.img

Dest: /var/lib/libvirt/backup/tubu1-clone/tubu1-

We can run a live backup
Trying to restore tubu1-clone from /var/lib/libvirt/backup/tubu1-clone/tubu1-clone.state
Waiting for restoration to complete
Starting dump of /dev/iscsi2/tubu1-clone_1344612236 to /var/lib/libvirt/backup/tubu1-clone/tubu1clone_vda.img
32000+0 records in
32000+0 records out
8388608000 bytes (8.4 GB) copied, 244.731 s, 34.3 MB/s
Removing snapshot /dev/iscsi2/tubu1-clone_1344612236
Cannot start domain restoration, tubu1-clone is running (maybe already restored after a live
backup ?)
Removing lock file for tubu1-clone

The backup creates a directory with these files:
# ls -l /var/lib/libvirt/backup/tubu1-clone
-rw------- 1 root root 284363322 Aug 10 17:23 tubu1-clone.state
-rw-r--r-- 1 root root 8388608000 Aug 10 17:28 tubu1-clone_vda.img
-rw-r--r-- 1 root root
2453 Aug 10 17:23 tubu1-clone.xml

Restore from backup to same VM:
# virsh shutdown tubu1-clone
# dd if=/var/lib/libvirt/backup/tubu1-clone/tubu1-clone_vda.img
of=/dev/iscsi2/tubu1-clone
# virsh restore tubu1-clone.state

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