--On April 19, 2006 6:40:27 PM +0200 Andrzej Kwiatkowski <andrzej.kwiatkowski@xxxxxxxxx> wrote:
Hi I'm going to build email-system based on cyrus with SAN storage. As an array i will use CX700. For every instance i'g going to build raid group from 9 146GB disks. I've noticed that in last version of imapd is possibility to separate mail files and meta files. Does it make sense to seperate mailboxes and metafiles, and/or sieve files, mboxlist partiotion when using SAN storage with big performance ? I know that with normal disk this is very important, bot it this situation i this this make no sense.
If you mean separate filesystems, I'd tend to say yes still, depending on your base OS. Linux for example keeps queues and caches in different ways than Solaris. Irregardless of what OS you use you'll want some volume management, and a filesystem that can atleast grow online such as ReiserFS. I've heard that ext3 can be resized online, but I've never seen it myself so can't say one way or the other there.
I've got one installation backed by a CX200 and the only issue we run into is I/O loading when we had the mail queues and the backend storage all on the same spindles. Once I seperated those out things got a lot better. We're talking quite a bit of I/O though, and the main mail store spindles also back part of the NFS server cluster as well.
We use a Linux 2.4 kernel, ReiserFS, on top of LVM, on top of MD in multipath mode -- the reason for the MD multipath is at the time there wasn't a working qlogic driver with builtin failover support.
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