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.
That's exactly what I need for reiserfs :-( . Darn. I guess that's something to note in the Cyrus FAQ - xfs makes backing up Cyrus easier.
Would be nice to have something like a 'cyrus_freeze' command. Maybe there is a way to do this with SIGSTOP/SIGCONT?
I was thinking about that, but came to the conclusion that it wouldn't save me from things like half-completed db writes, etc. I couldn't SIGSTOP the master (to prevent new LMTP deliveries) without also preventing new IMAP connections :-(
Craig Ringer
