Re: [libvirt-users] how to get disk snapshot size
On Sun, Mar 15, 2015 at 10:28:30PM +0800, Yitao Jiang wrote:
Hi,guys
I wanna to get the disk snapshot size, but found nothing libvirt commands
related,except qemu-img.
I create two disk snapshots, but nothing return its' size
The below does not seem like snapshots. They're *internal* qcow2
snapshots (original and delta are on the same file).
A quick example of disk snapshots:
List the current active device:
$ virsh domblklist cirrvm
Target Source
------------------------------------------------
hda /var/lib/libvirt/images/cirros-0.3.3-x86_64-disk.img
Create a 'disk-only' external snapshot:
$ virsh snapshot-create-as --domain cirrvm snap1 \
--diskspec vda,file=/export/vmimages/sn1.qcow2 \
--disk-only --atomic
List again the current active block device:
$ virsh domblklist cirrvm
Target Source
------------------------------------------------
hda /export/vmimages/sn1.qcow2
Get info about the disks involved:
$ qemu-img info --backing-chain /export/vmimages/sn1.qcow2
image: /export/vmimages/sn1.qcow2
file format: qcow2
virtual size: 39M (41126400 bytes)
disk size: 196K
cluster_size: 65536
backing file: /var/lib/libvirt/images/cirros-0.3.3-x86_64-disk.img
backing file format: qcow2
Format specific information:
compat: 1.1
lazy refcounts: false
image: /var/lib/libvirt/images/cirros-0.3.3-x86_64-disk.img
file format: qcow2
virtual size: 39M (41126400 bytes)
disk size: 14M
cluster_size: 65536
Format specific information:
compat: 0.10
--
/kashyap
[root@cskvm01 qcow2]# qemu-img info
/mnt/e6758700-af68-3c06-ade3-53f5f9b93507/e2cf6551-0d2c-4382-a86c-8ba633954ff2
image:
/mnt/e6758700-af68-3c06-ade3-53f5f9b93507/e2cf6551-0d2c-4382-a86c-8ba633954ff2
file format: qcow2
virtual size: 5.0G (5368709120 bytes)
disk size: 1.0G
cluster_size: 65536
Snapshot list:
ID TAG VM SIZE DATE VM CLOCK
1 4fc42d73-8257-42bd-8807-81700fd3c689 0 2015-03-15 21:05:55
01:05:53.583
2 2fd6aeab-cb26-446d-b1c6-e8d70d33f651 0 2015-03-15 21:50:35
00:00:00.000
After wrote data to the disk, then create another snapshot
[root@cskvm01 qcow2]# qemu-img info
/mnt/e6758700-af68-3c06-ade3-53f5f9b93507/e2cf6551-0d2c-4382-a86c-8ba633954ff2
image:
/mnt/e6758700-af68-3c06-ade3-53f5f9b93507/e2cf6551-0d2c-4382-a86c-8ba633954ff2
file format: qcow2
virtual size: 5.0G (5368709120 bytes)
disk size: 3.9G
cluster_size: 65536
Snapshot list:
ID TAG VM SIZE DATE VM CLOCK
1 4fc42d73-8257-42bd-8807-81700fd3c689 0 2015-03-15 21:05:55
01:05:53.583
2 2fd6aeab-cb26-446d-b1c6-e8d70d33f651 0 2015-03-15 21:50:35
00:00:00.000
3 63815565-3a06-4366-a1b3-bfeb9c4a07b4 0 2015-03-15 22:22:43
00:00:00.000
VM SIZE column still show 0
Here is my environment
qemu-img version 0.12.1, Copyright (c) 2004-2008 Fabrice Bellard
libvirtd (libvirt) 0.10.2
CentOS release 6.5 (Final) 2.6.32-431.el6.x86_64