Am 11.11.2011 10:55, schrieb Daniel P. Berrange: > On Fri, Nov 11, 2011 at 10:38:20AM +0100, Kevin Wolf wrote: >> Am 11.11.2011 01:11, schrieb Anthony Liguori: >>> I did a brain dump of my understanding of the various storage requirements >>> for >>> live migration. I think it's accurate but I may have misunderstand some >>> details >>> so I would appreciate review. >>> >>> I think given sections (1) and (2), the only viable thing is to require >>> cache=none unless we get new interfaces to flush caches. >> >> Yes, I think we should strongly recommend cache=none/directsync, but not >> enforce it. As you said, for clustered filesystems other options should >> work, so we should allow users to choose to make use of that. > > WRT libvirt, we have a concept of 'tainting' for guests. We set taint > flags whenever the management application requests a config, or performs > an action that we know to be potentially dangerous. These end up as log > messages in the per-guest logfile, so when users report bugs we can see > from the log that something "bad" has been done to the guest. > > At the very least, it sounds like we should make libvirt mark guests as > tainted, if they have been migrated with cache != none, so this is easily > identifiable by BZ support people. > > We might also want to make a libvirt host level config option to allow > host admins forbid migration without cache=none.
Yes, I think this would be a good approach. Kevin