[CentOS] clustered mail server?

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.