[Maia-users] Performance Issues

[Robert LeBlanc]

Shue, Daniel G. wrote:

> You can see the SA Check is the culpret.  Is there anything I can do to
> log what SA does and get something like this so I can see where the
> bottle neck is?  Is there anything else I can do to speed up SA?

You can get a general diagnostic by trying something like:

  spamassassin -D -t < email.txt

and watching the output to see where it hangs the longest.  Start from
there before you go needlessly disabling beneficial features.

It's also worth pointing out that depending on your hardware and your
mail traffic load, a processing time of 6-10 seconds per item may not be
unreasonable, particularly if you add the FuzzyOCR plugin (which can
boost the processing times by another 2-4 seconds for items that contain
inline images).  SpamAssassin's tests are thorough, and you can't
reasonably expect to insert a filter like this into your mail system
without reducing your mail system's overall throughput somewhat.  You
can make SpamAssassin less thorough in its checks, of course, to speed
things up a bit, but that rather defeats the purpose.

What you need to consider when you're thinking about adding spam
filtering to an existing mail system is how that extra filtering delay
is going to need to be balanced out to achieve the throughput levels you
want.  You may discover that to solve your bottleneck problem you need
to run a second amavisd-maia box in parallel, sharing the same Maia
database.  That would put more hardware to work where it's needed the
most, and if your mail volume calls for it you could add a third,
fourth, fifth amavisd-maia box to the array down the road.

It's also important to realize that spam filtering is not a job you
really want to assign to that five-year-old PII-300 that's been
gathering dust in your basement.  A lot of people make the mistake of
thinking that they can use some old spare hardware to do the job, but
they quickly discover that spam filtering is a very resource-intensive
task, and their bottleneck just constricts further when the hardware is
overloaded.  Particularly now that we've entered the OCR era, the
resource requirements of your amavisd-maia box are only going to grow.

-- 
Robert LeBlanc <rjl at renaissoft.com>
Renaissoft, Inc.
Maia Mailguard <http://www.maiamailguard.com/>

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