On Tue, 2003-05-13 at 10:39, Stephan Poehlsen wrote: > Hi, > > How would you realize a realtime email-backup across two different > computers in two different computer-centers? > > Let's say I have a mail-server A in city A and a backup-mail-server B > in city B. So if an airplain crashs one computer-center, no email gets > lost. > > I think all mail must be forwarded from server A to B (and must be > acknowledged from B) before server A acknowleges incomming mail.
You could use DRBD to have your spool-directory mirrored. If machine A goes down, B mounts the DRBD device and takes over the IP address of your mail-service. Voila, you're up again. Downtime: a few seconds... The only real problem I see: If you really want to distribute your servers across two cities (!), you'll need some really good (i.e. stable) connection between both servers or you may face a split-brain situation. A fast Uplink may be nice to as you have to re-sync your whole device every time one of your servers go down. Typically DRBD has some Gbit interconnect through a crossover cable to prevent such a situation due to a switch-failure or something else and provide reasonable fast re-sync times. > Does there exists a solution? Maybe with qmail? The scenario above is completely MTA independent - you can use qmail, sendmail, postfix, exim, courier-mta, $whatever... best regards, Markus -- Markus Oswald <[EMAIL PROTECTED]> \ Unix and Network Administration Graz, AUSTRIA \ High Availability / Cluster Mobile: +43 676 6485415 \ System Consulting Fax: +43 316 428896 \ Web Development
