Performance suggestions?

[Joel Colvin]

I am running two identical servers handling inbound mail equally.  Both have
MailScanner-4.14-9
Spam-Assassin-2.53
Razor-2.22
Both are Pentium 4 1.8Ghz systems.

I do not do virus checking on these systems.
I rarely get SpamAssassin timeouts.
I do RBL checking within MailScanner and SpamAssassin.
These servers each handle about 30,000 messages a day.

Most of the time the mqueue.in directory has less than a hundred files but
about once or twice a week we get backlog of mail and the mqueue.in reaches
about 3000+ per server.  Why I get all the email at once is a different
issue.  I'll still need to see if I can through the mail more quickly.

Uptime shows a low normal processor load. (Usually a fraction below 1.)

I concern with the message delay.  This morning we had up to a two hour
delay in passing from mqueue.in to mqueue.

I have adjusted one machine's MailScanner.conf while leaving the other alone
to try to see if I can get MailScanner to get through its queue faster but
without luck.  Once sendmail gets the mail in mqueue, it flows out nicely.

Today, as per the recent thread on batches, I am trying one system with a
lower batch size while the other is at the defaults.

Any other suggestions I could try?

Joel