[CentOS] RAID on Email Server

[Matt]

>> I have an email server running Exim, Dovecot, Spamassassin, Clam, etc.
>
> Firstly, I'd drop dovecot completely, cyrus-imapd has, for me, been a lot
> faster and better optimised for situations where you have more than a few
> hand full of users.
>
> Secondly, exim configs out of the box on CentOS are *really* not optimized
> for performance at all. If you handle more than a few thousand emails an
> hour, I dont be surprised if exim is to blame for jamming your i/o pipe just
> trying to work out which email to attempt delivery for next.

This is a Directadmin type server.  So I really have no options on
changing services.  I am running exim version 4.60 and I wander if
updating to 4.69 may help out.

Matt