Performance Improvements Inside!

Kelly Hamlin fizz at BOMB.NET
Fri Jun 7 14:03:24 IST 2002

I thought id pass on some suggestions/improvments that were passed to me.
First off. In, try reducing your logging from loglevel 9 to 7
this will eliminate all the deferred messages from occuring in your logs
which was on my system making syslogd take up over 60% of my cpu.

Switching off disinfection would now make it run considerably quicker.

Other than those things, the reason for the slowdown is unfortunately the
addition of new features, many of which you are using. A good example is the
virus subject line tagging ({VIRUS?}). This involves checking the entire
headers for a subject line already including this text, as you never want it
tagged more than once, and then modifying the string of headers to include
the new text.

One point of note: I would question (in the current "Klez" climate) whether
trying to disinfect viruses from messages is even worth the bother any more.
It's very expensive (involves calling the virus scanner 2 more times) and it
very rarely creates any useful results. Word macro viruses (which it can
disinfect) are few and far between compared to things like Klez.

The vast majority of your CPU time is being stolen by syslogd, logging
useless info to /var/log/mail/maillog about users who are over their quota.
If you decrease the LogLevel in your, or increase the logging
"priority" of mail in /etc/syslog.conf, you could drastically reduce this.

I would also question using "sendmail -q1m" in your rc.M file. This is
forcing a run of the entire outgoing queue every 1 minute, which is
contributing to the load (by starting a queue run before the previous queue
run has finished) and also is contributing to the syslog load, by creating
yet more "message would exceed their quota" log entries.

You will also find, in Linux, that appending to the end of a small file is
quicker than appending to a huge file (which your maillog is). If you roll
your logs more frequently, that will again help reduce your syslog load

                ( o o )
| [Kelly Hamlin]
| kellyh at
|   .oooO
|      (  )    Oooo.
+--- \  (----(   )----------------------------+
          \_)    ) /

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