[Mimedefang] making spamassassin less sensitive

[Kris Deugau]

Muhammad Talha wrote:
> i recently shifted my mail server to Mimedefang i have following
> hardware and software installed .using default mimedefang and
> spammassain rules

What sort of mail load are you getting?  (messages/minute, messages/day,
etc)  Without knowing what sort of processing load you're putting on the
system it's a little hard to say where the bottleneck might be.

> Processor Pentitum III

What speed?

> RAM 256MB

Buy more memory.

> Swap 512

Swap doesn't really help for MD/SpamAssassin processing;  once you start
hitting swap with either program your system will slowly bog down
further and further- although for MD it's a *little* less painful than
SpamAssassin running independently.

> Sendmail-8.11.12

I think you mean 8.12.11 here;  I don't recall seeing 8.11.12 ever.

> Due to lack of RAM system sometime take all the Ram+Swap and i have
> to restart mimedefang

Buy more memory.

> i want to make Spamassain less sensitive so that i can save more
> memory. Steps i want to take

Hmm.  Difficult due to the way SpamAssassin works.....

> 1) Change mimedefang-filter
> if (-s "./INPUTMSG" < 100*1024) {
> TO
> if (-s "./INPUTMSG" < 50*1024) {

A nice idea, but not likely to help much.  I *have* seen spam in the
50-100K range.

> 2) Change sa-mimedefang  ( required_hits   12 or higher )

Not going to help at all.  This won't change the memory usage.  SA runs
*all* tests, then totals up the scores for the ones that hit.

> 3) change mount /var/spool/MIMEDefang as tmpfs ( size 256m )

A 256M TMPFS mount here is a REALLY bad idea with the hardware you have
now.  Buy more memory.  (For comparison, I have a 100M TMPFS partition
for /var/spool/MIMEDefang on a machine with 512M physical memory.  Due
to the memory load for other processing on this particular machine, even
that is probably a bit high.)

> 4) how to enable embedded Perl interpreter ? to reduce memory usage

Sounds like a useful idea, although you'll have to consult the man
page(s) (man mimedefang, man mimedefang.pl, man mimedefang-filter) to
find out what to do.

> 5)  Should i had to remove some rules from /usr/share/spamasssain ??

This is really about the only way to reduce the memory usage of
SpamAssassin- and doing so will likely make it *far* less effective.

> any ideas and throught will be helpful ?

Buy more memory.  RAM for a PIII system should be pretty cheap;  ~$80CDN
for 256M I think.  I would go to *AT LEAST* 512M, if not 768M or a full
gig.  As I've noted above, swap doesn't really help here because it's
*far* too slow.  And a TMPFS partition for MIMEDefang's working
directory won't help if it keeps getting swapped out to disk (or causes
something *else* to get swapped out to disk...).

-kgd
-- 
"Sendmail administration is not black magic.  There are legitimate
technical reasons why it requires the sacrificing of a live chicken."
   - Unknown