> I'm also running into an issue where occasionally the snapshot fails - > it's taken while reiserfs is in the middle of a transaction, and the > journal can't be replayed on mount because the snapshot is read-only. > This is more of an LVM issue than anything else. I get around it by > syncing the disk before taking the snapshot, and by deleting the > snapshot and trying again if it's not useable.
I've been using XFS on LVM and I think it doesn't have the problem you describe. With XFS, you have to call 'xfs_freeze -f' before taking the snapshot, then you 'xfs_freeze -u' it again. > I'd love to know of a way to ask cyrus to defer message delivery briefly > and make sure everything is in sync. That way I could signal cyrus to > "sync up and pause", do the db conversions, snapshot the volume, and > resume cyrus. I'd prefer to avoid killing and restarting the master > during the normal backup process. Would be nice to have something like a 'cyrus_freeze' command. Maybe there is a way to do this with SIGSTOP/SIGCONT? Simon