----- Original Message ----- > From: "Eric Blake" <eblake@xxxxxxxxxx> > To: "Andrew Martin" <amartin@xxxxxxxxxxx> > Cc: libvirt-users@xxxxxxxxxx > Sent: Friday, July 22, 2016 10:40:54 PM > Subject: Re: Blockpull behavior when interrupted > > On 07/22/2016 11:30 AM, Andrew Martin wrote: > > > > > Thanks, that was a helpful overview. To clarify, block commit is changing > > the backing files,but even though it is doing that, the data is consistent > > even if it is interrupted? > > Yes, the guest's view of the data is consistent. Intermediate backing > files may have contents that don't correspond to any historical state > seen by the guest, but the guest view is never compromised. > > > > > Reviewing the presentation brought up another question. I have been > > thinking > > about installing qemu-guest-agent so I can use --quiese with > > snapshot-create-as, > > however I have a couple of questions: > > * does the guest agent always report back to libvirt on the host if it > > succeeds, > > fails, or has an error when attempting to sync(2)? > > Guest agents only work if you can trust the guest (a malicious guest > could just lie), but in general, for a trusted guest, yes, the agent > will inform the host if there was an error quiescing data, at which > point libvirt will mark the overall command as failed. > > > * isn't it a security risk to allow the guest the ability to communicate to > > the > > host via the guest agent port? > > It's always a security risk to trust a random guest to do anything, if > you don't trust the guest to begin with. --quiesce, and the guest agent > in general, is only useful for trusted guests. > > > > > Also, any thoughts on utilizing ZFS snapshots in lieu of internal or > > external > > qcow2 snapshots, at least for backup purposes? Utilizing zfs send/zfs > > receive > > would be nice for performance when sending full image backups to a remote > > server. > > Patches are welcome, although ZFS may be tricky because of licensing > questions (I'm not a lawyer, but I know enough to not touch ZFS as long > as its current license doesn't play nicely with the Linux kernel) Thanks for the clarification on these points! _______________________________________________ libvirt-users mailing list libvirt-users@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvirt-users
