performance hints (6.2)

[Chuck Swiger]

On Aug 17, 2007, at 1:00 PM, Mark Messier wrote:
> I've got a freebsd 6.2 system, dual 2Ghz 5130 cpu, 4g ram, with raid5
> Adaptec 2120s, running not much more than /usr/ports/mail/imap-uw
> and I'm having performance problems with only 20 IMAP users.
>
> I'm not swapping.. cpu is mostly idle, so I figure it must be I/O
> performance.  Just to confirm, is that what the following show?

You're seeing upwards of 400 I/O transactions per sec, so your system  
is definitely I/O bound.

Note that RAID-5 is not an ideal choice for a filesystem which is  
going to be used for balanced read-write operations-- it's best used  
for read-only or read-mostly purposes.  You are probably using the  
default mbox mail format; you're likely to find that using maildir  
would work much better when running on a RAID-5 volume.

Regards,
-- 
-Chuck