thanks,i'll keep looking for it and share with others. 2012/5/30 Eric Blake <eblake@xxxxxxxxxx>: > On 05/29/2012 10:22 AM, xingxing gao wrote: >> to create snapshot ,I did step below: >> virsh snapshot-create-as centos snap1 --disk-only --atomic --no-metadata >> virsh snapshot-create-as centos snap2 --disk-only ...... >> ........................ >> virsh snapshot-creates-as centos snap10 ..... >> then i got 10 snapshot of a vm, >> to revert, i just did the follow step: >> 1 destroy centos >> 2 editor="sed -i 's/centosdisk.snap10/centosdisk.snap1/g'" virsh edit centos >> 3 rm -f centos.snap{2,3,4,5,6.....} > > Yes, that will be sufficient to revert to the state of the first disk > snapshot, and on booting the 'centos' VM, your domain will have to run > fsck in order to recover to the fact that the file system was not in a > clean state at the time of the snapshot (basically, booting from your > disk snapshot is the same as booting as if you had yanked the power cord). > >> 4 start centos >> is these steps correct? >> and another question is ,when i revert to a snapshot,some files of the >> vm's system missing,does this have any relation with the disk cache >> mode (writeback,writethrough,none,etc.)???how could i avoid that >> happen?? > > You can install the qemu-ga guest agent in the guest, wire it up in the > host XML describing that guest, and add the --quiesce option to your > snapshot-create-as command in an effort to have the guest freeze file > systems before taking the snapshot. The end result will be that the > file system is in a sane state (as if you had cleanly shut down), rather > than in an incomplete state (as if you had yanked the power cord). > > I know that qemu-ga is available as part of the latest Fedora package, > and that it was designed to be compiled for older Linux and also for > Windows guests, although I don't personally have a good pointer for > where to get the best version of qemu-ga for your specific guests. > Maybe others can chime in here. > > -- > Eric Blake eblake@xxxxxxxxxx +1-919-301-3266 > Libvirt virtualization library http://libvirt.org > _______________________________________________ libvirt-users mailing list libvirt-users@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvirt-users