On Fri, 04 Apr 2003, Phil Chambers wrote: > I am concerned that because Cyrus is a "black box" system which keeps track of its > own internal organisation we may have problems if we restore a disc from our > backups. It will take hours to do a backup and the files within the Cyrus structure > will be changing as we do it. Are there going to be problems with inconsistencies > between files?
There are two answers to this. The first is that doing snapshot backups should be possible on most plausible platforms, either by dropping a mirror off (requires mirroring, of course) or using fssnap (Sun) or LVM (Linux) to do a hot backup. The second is that in practice you can recover a mailbox by spinning on the files and then using reconstruct to rebuild the metadata. The worst you're going to do is break the unread flags and suchlike. > There is a secondary, but important use of our current backup service, which is to > dig users out of a hole when they make mistakes: Occasionally a user will > accidentally delete a message or even a whole folder and then come and ask if I can > recover it for them. We do that all the time. We pull the entire mailbox back, then grep for what the punter wants. > With our current backup system it is ussually very easy because I have no problem > identifying the relevant files to be recovered. I seems to that it will be > impossible to recover deleted messages because I will not be able to identify the > files which I need. If I can identify the files, presumably there is no way to get > them back into the Cyrus system? If you can identify them by size or date, you just put them back into the mailbox and reconstruct it. ian