Will snapshot-revert restore the processor and memory state of the VM as it was at the time of the snapshot? -- Gary Jackson On 9/19/17, 11:10 AM, "libvirt-users-bounces@xxxxxxxxxx on behalf of Doug Hughes" <libvirt-users-bounces@xxxxxxxxxx on behalf of doug.hughes@xxxxxxxxxxxxxxx> wrote: On 9/19/2017 9:56 AM, Martin Kletzander wrote: > On Tue, Sep 19, 2017 at 01:28:45PM +0000, Jackson, Gary L. wrote: >> >> I would like to make a snapshot of a running VM, let it continue to run >> after the shapshot, and then at some later time roll back the VM to >> that previous running state. Can I do that with libvirt? If so, how? I >> understand that this will cause all kinds of havoc with things like >> ongoing TCP connections, and I accept that risk. >> > > Check `man virsh` and the description to commands `snapshot-create-as` > and `snapshot-revert`. If more information is needed, feel free to ask, > although if deep knowledge is required I might need to rely on someone > else to reply then. agreed. This is definitely achievable with snapshot-create-as. You'll prefer to shutdown the VM to make it work, but it can be done live using the --running flag. I've never tried this. The man page isnt entirely clear but it seems like it will effectively reboot to the state when the snapshot was taken. Mechanics wise, you take the snapshot. Now you have a new disk image file (usually with -snap, but you can name it whatever using snapshot-as), that will be recording the changes that are happening to the OS. The old image at the time of the snapshot is still there under the original name. If you look in the xml file, you'll see it has changed the path of the disk image to the new snapshot file. The new snapshot is a 'sparse copy' in that is recording all of the new changes happening, but it has a reference pointer pointing back to the original image for things that have not changed. At any point, you can shut down your VM and boot off the original image, which discards all of the changes. Or you can decide that you want to 'blockcommit' all of the changes back to the original image which you can do online without impact. (I use this with ZFS replication to provide rollback capability per VM image to another host in case of host failure) _______________________________________________ libvirt-users mailing list libvirt-users@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvirt-users