On Aug 25, 2010, at 10:15 AM, Timo Sirainen wrote: > > But if secondary server allowed changes, this is the difficult step to > do correctly. For example lets say in first server: > > 1. It rsyncs user foo > 2. User foo changes message A flag to \Seen > 3. User foo deletes message B > 4. User foo saves a new message C > 5. The server crashes > 6. Secondary server goes up, but 2-4 changes weren't resynced yet > 7. User foo logs in and changes message D's flag to \Seen > 8. Primary server goes back up > 9. You rsync .. how? If you make primary server look exactly like > secondary server, you message C gets lost. If you copy new files, now > message A and message D gets duplicated, because their filename changed > due to the flag change. Also message B becomes undeleted. > > Of course assuming this happens rarely enough, those aren't a huge > problem, but the server move isn't always transparent to users and > you'll get errors in Dovecot's logs.
First off, thanks. It will happen rarely (2-3x/year most likely base on prior power outages) and if a couple users get a duplicate message or unread when read issue they can file a complaint :) The transfer wouldn't be transparent - I would force them to webmail on the backup (maybe even force POP3?). Now to figure out where the virtual user data is...sigh
