----- Original Message ----- > From: "Eric Blake" <eblake@xxxxxxxxxx> > To: "Andrew Martin" <amartin@xxxxxxxxxxx> > Cc: libvirt-users@xxxxxxxxxx > Sent: Friday, May 23, 2014 7:30:44 PM > Subject: Re: Live snapshots of a single block device > > On 05/23/2014 12:16 PM, Andrew Martin wrote: > > >> --quiesce requires the guest to be running to work, while --memspec > >> forceably stops the guest (the migration algorithm must pause, even if > >> --live minimizes the pause to a fraction of a second). > > Would calling snapshot-create-as with --disk-only and --quiese still > > succeed > > on a VM that is stopped (since the disk would already be consistent, it > > would > > just call "qemu-img create")? > > For an offline guest, --disk-only makes no difference (there is no > memory to worry about); and you are correct that the disk is consistent > (assuming the OS has a clean shutdown before going offline). Yes, > calling 'qemu-img create' is basically what libvirt does for an offline > external snapshot. > > However, a paused/stopped guest cannot respond to a quiesce request (the > guest agent only works if the guest is running), so your attempt to use > --quiesce would fail; you'd have to omit the parameter if the guest is > stopped. Okay, that makes sense to me. Thanks for the clarification! Andrew _______________________________________________ libvirt-users mailing list libvirt-users@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvirt-users
