MailScanner & Hyper threading

[Matt Kettler]

At 10:14 AM 5/12/2004, pn1013 wrote:
>We have a MailScanner box which seems to be cursed, it's a hyper threading
>Pentium 4 processor box with 1 gig of ram and 7200RPM disks.  The problem
>we're seeing is that it doesn't seem to be able to process much more than
>5000 messages per day without having huge backlogs on the inbound queue
>regardless of what we do.
>
>Here's the config:
>
>Sendmail 8.12.x
>DCC
>Razor
>Spamassassin 2.63
>RBL's enabled
>Local Caching Nameserver
>/var/spool/MailScanner/incoming in tmpfs
>/tmp in tmpfs
>Bayes DB's are held in TMPFS & backed up to disk regularly in case of
>reboot.

Personally, I doubt that HT is causing any of your problems. However, I'd
be wondering what your MailScanner children count is set to. I'd not treat
a HT box as if it had 2 cpu's for this purpose, I'd treat it more like it
had 1.2 or 1.3 cpus.

Also number 5000/day is suspiciously close to one message every 15 seconds,
so I'd be concerned about timeouts.

I'd first suggest trying running a test email through SA by hand:
         spamassassin -D <sample-nonspam.txt

That can be very informative and show you where timeouts might be occurring
in SA. Little issues in firewall configurations can cause major problems
here, particularly with DCC and razor.

Now, spamassassin -D will run much slower than calls via MailScanner, but
it shouldn't be 15 seconds slow. My 2ghz non-HT p4 box can do it in 7
seconds here, with the bayes db's on normal disk, with antidrug and SURBL
added on top of all the above.

 From there, if you're using spam lists in mailscanner.conf, try turning
those off.

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