Hi I'm looking for a redundant mail storage. Not just a seconday MX where mail is temporarily stored on a second server, but just that when one server crashes another server goes on with its normal tasks. For mail I think it would be nice if all new messages go to both servers, and when a message is read, it is removed from both servers. During downtime then one server goes on with the normal tasks, and after some time the server sends the server that is back up the data it missed.
Using a single mailfile this is not possible I think, unless you write something with a procmail script that delivers to two mailfiles, and hack the pop3-daemon to delete files from both hosts. With maildir however, this looks much better. Something like unison would be nice then, since it seems to support bidirectional synchronisation; and since there is no central database of the messages stored, it uses a diff to change the other server. (Rsync is worse, because of the unidirectional synchronisation I think... I might be wrong.) Maybe also coda is a solution, but I never looked at it soo close, and it looked a bit complex at first. However, my favorite pop/imap-server at the moment is Cyrus :-) With Cyrus I also see single files per message, but also a centralized database per folder. I think this is my problem. This file is changed on both hosts if e.g. a mail is delivered to both hosts when they aren't able to reach eachother... Is there any solution to this problem? (Except switch to a mail server that uses Maildir's like qmail...) Thank you in advance, Paul
