From: Stan Hoeppner <stan@hardwarefreak.com> Subject: Re: [Dovecot] SSD drives are really fast running Dovecot
Yes. Go with a cluster filesystem such as OCFS or GFS2 and an inexpensive SAN storage unit that supports mixed SSD and spinning storage such as the Nexsan SATABoy with 2GB cache: http://www.nexsan.com/sataboy.php
I can't speak for OCFS2, but after several years' experience with the filesystem I strongly recommend NOT using GFS/GFS2. Its locking model is incredibly slow (500 locks/second on a filesystem mounted with quotas enabled and noatime) and results in dire performance - plus there's a known crash vulnerability if files are repeatedly renamed in large directories (this bites us regularly...)
GFS2 isn't an "enterprise" filesystem by any stretch of the imagination, despite what a number of enthusiastic salespeople might try to convince you of. We're lucky to keep the GFS servers up for more than a week at a time.