On Fri 22 Jan 2016 09:02:10 PM CET, "Dr. David Alan Gilbert" <[email protected]> wrote:
>> >>>> In general, what do you do to make sure that the data in a new >> >>>> Quorum child is consistent with that of the rest of the array? >> >>> >> >>> Quorum can have more than one child when it starts. But we don't >> >>> do the similar check. So I don't think we should do such check >> >>> here. >> >> >> >> Yes, but when you start a VM you can verify in advance that all >> >> members of the Quorum have the same data. If you do that on a >> >> running VM how can you know if the new disk is consistent with the >> >> others? >> > >> > User error if it is not. Just the same as it is user error if you >> > request a shallow drive-mirror but the destination is not the same >> > contents as the backing file. I don't think qemu has to protect us >> > from user error in this case. >> >> But the backing file is read-only so the user can guarantee that the >> destination has the same data before the shallow mirror. How do you >> do that in this case? > > I think in the colo case they're relying on doing a block migrate to > synchronise the remote disk prior to switching into colo mode. Yes but this is a general API that can be used independently from COLO. I'd say if we want to allow that we should at least place a big warning in the documentation. Berto
