Kent Borg wrote: > Question about setting up Postfix/Dovecot machine as a backup e-mail server. > > I should set up an e-mail backup. I have another static Linux machine I > could use, that has a static IP address, but the question is how to > configure it. Once upon a time I had a machine set up as a backup, but it > only queued up messages until the primary machine came back on line. But > sending machines do a decent job of queuing messages anyway, so that doesn't > buy much, so I turned it off.
This is called a Secondary MX, although you can have any number of them. > I see three possibilities: > > * Set up a backup that just queues messages. > > I don't really see the point. It provides the illusion of high uptime, which might be important for you. In any case, it's a set of suspenders to go with your belt. > * Set up a second server that acts like the first. > > I worry when I might do a cutover the IMAP server will confuse the > client. The client won't see old messages that were on the primary > server and so deletes its local copies. Yeah, that would be bad. > * Set up something more clever that keeps the primary and backup in sync so > both IMAP servers hold the same messages. High-availability is hard, although this is the easiest case: you list both machines in your MX records, and have your MTA deliver to a shared filesystem. DRBD is the usual choice. Then your IMAP service has to deal with all your mail in the shared filesystem. -dsr- _______________________________________________ Discuss mailing list Discuss@blu.org http://lists.blu.org/mailman/listinfo/discuss