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 >