bottlenecking?

[Jim Levie]

On Wed, 2002-09-25 at 17:48, Julian Field wrote:
> Quoting Tim Tyler <tyler at BELOIT.EDU>:
> > Mailscanner experts,
> >    We are currently running mailscanner 2.6 on AIX4.3.3
> > systems.  Occassionally, we have noticed that mailscanner clogs up at
> > peak
> > periods and can't seem to process email for hours.  This means that local
> > or remote mail is stuck in /var/spool/mqueue.in for hours before
> > eventually
> > making it to the normal sendmail mqueue (if at all).   If I kill the
> > mailscanner process and restart it everything gets processed nearly
> > immediately.
> >
> >   Isn't mailscanner_check running in crontab supposed to make sure that
> > the
> > process is running ok?  It would really be better if it simply killed the
> > existing process every time and restarted it.  I suggest this because if
> > it
> > thinks the process is running ok when it isn't, then its useless.
> > Anyone's
> > thoughts about killing and restarting the process every 20 minutes or so?
> >
> >   Are there any other suggestions for configurations that can minimize
> > bottlenecking?
>
> Not sure why you are hitting the problem. However, what you could do is set
> the "Restart Every" interval much shorter. Then MailScanner will re-exec
> itself more frequently, which will probably work around whatever the
> underlying problem is. "Restart Every = 1200" would make it restart every 20
> minutes.
>
FWIW: I've seen this sort of problem to one degree or another with every
V3 version of MailScanner that I've deployed. Its too soon to say if v4
will have the same sorts of problems. My solution is to use a smart Perl
monitor, rather than a shell script, to manage the MailScanner
processes. The perl code watches for excessive CPU consumption,
excessive process size, or a MailScanner that's run longer than it
should. If any of the boundary conditions are seen the offending process
is killed and restarted. While I suppose a clever shell script could be
written to do the same thing it was very easy to do with Perl and I took
the path of least resistance.

The V4 implementation brings new challenges. Not only do you have the
mater process, but you also have a number of child processes to deal
with. I'd like to see a pid file for each of the children, perhaps with
a name of the form mailscanner1.pid, mailscanner2.pid, etc. And it would
be awfully nice is killing the master process would cause it to reap its
children.
--
The instructions said to use Windows 98 or better, so I installed
RedHat.