On Tue, Jun 28, 2011 at 01:07:02AM +0900, [email protected] wrote: > > -Kei, as to Q2 in your original message...I have absolutely no idea why the > > image is bigger, but hopefully one of these days I'll get time to get back > > into the libvirt code and help you out! :) > > This is another essential issue here. I just wrote "when I call snapshot() > once, what's happen original image" at the previous e-mail, but when we try > to call snapshot() over and over again, original disk image is bigger and > bigger. I have no idea how eventually bigger disk image is. I think the > reason why image size is bigger is that snapshot is included into original > image ....... Anyway, I am waiting you get back :).
Although I'm not familiar with libvirt and not an export of qemu block layer. Qemu savevm (I'm assuming libvirt maps it to qemu savevm) takes snapshot of not only disk image, but also guest RAM. Thus guest can re-execute at the point of snapshot. The difference is guest RAM size, I think. Regarding to freeing snapshots of qcow2, major file systems don't provide a way to free once-allocated-blocks except truncate. So qcow2 doesn't have a way to free unnecessary blocks. You may need btrfs or modern advanced file systems that supports punching hole and discard. -- yamahata _______________________________________________ Mailing list: https://launchpad.net/~openstack Post to : [email protected] Unsubscribe : https://launchpad.net/~openstack More help : https://help.launchpad.net/ListHelp
