Christopher Chan wrote:
re: mail servers specifically, there are two seperate classes of storage that would need replication... One is the mail spools and queues as used by the MTA (postfix, sendmail, etc), and the other are the user mail folder(s) as used by the local delivery agent (procmail or whattever), and read by the mail client (pop, imap).
No, mail spools/queues do not need replication. Stuff in the queue are usually deleted in a second and such dynamic change is not worth replicating. If you do put the queue on a distributed filesystem, in most cases you cannot have more than one instance running save for sendmail.
outbound mail can sit in queues retrying for hours negotiating their way into the greylists of the likes of Yahoo. I guess if you don't mind the possibility of messages getting lost around a server failure event, then its no big deal, for sure.