[Mimedefang] Memory Usage

Wes Peters barnaclewes at gmail.com
Fri Mar 18 11:39:25 EST 2005


On Fri, 18 Mar 2005 07:24:21 -0500 (EST), David F. Skoll
<dfs at roaringpenguin.com> wrote:
> On Fri, 18 Mar 2005, Jonathan Maliepaard wrote:
> 
> > I run a small ISP and at 9am (now) am processing about 5000 delivery
> > attempts an hour. I have never noticed this before, but when running
> > "top" and sorting by memory usage, I see that each Mimedefang process is
> > using about 36Mb of ram. Is this normal?
> 
> Yes.  SpamAssassin uses a lot of memory.
> 
> > I have 1.5GB of ram installed
> > and it is using the lot. Can anyone offer me any advice on if I have
> > sufficient processes open, or whether I should stuff some more ram in
> > and  increase the processes?
> 
> If your server is performing well, don't worry about it.  (Seeing almost
> no free memory is perfectly normal on a Linux system; Linux tries to use
> all the memory it can for disk buffers.)
> 
> One thing you should try is turning on the embedded Perl interpreter.
> This can help reduce memory per Perl slave.

Most UNIX-ish memory reporting tools don't show you the real
memory usage of a process, they just show you the part that is
easiest to account for.  FreeBSD, for instance, shows SZ (memory
size) and RSS (resident set size), but they're both misleading,
because it is adding up the size of all the memory pages charged
to the process, and not taking into account if those pages are
shared.

The important statistic to look at is swapping activity.  If bursts of
mail send your system into a frenzy of swapping, you need either
more memory or fewer max slaves.

-- 
Against stupidity the very gods Themselves contend in vain.
                                         Friedrich Schiller



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