Mysterious MailScanner hangs

[Kris Zabriskie]

Eric,
I just skimmed through your message quickly.  We had a VERY similar problem.
What we do now (and it works) is in crontab we do this:

0,5,10,15,20,25,30,35,40,45,50,55 * * * * [ -x /usr/bin/resms ] &&
/usr/bin/resms >/dev/null 2>&1

resms is simply a script that kills all processes of MailScanner and then
runs the ./bin/check_mailscanner binary.

Hope that helps... and again, I apologize if this has nothing to do with
your problem, I just skimmed.

Kris Zabriskie
Network Admin / Consultant
I-Tech Inc.
zabriskw at itech.net
717-657-3035


----- Original Message -----
From: "Eric McClelland" <emcc-mailscanner at CTCNET.COM>
To: <MAILSCANNER at JISCMAIL.AC.UK>
Sent: Friday, July 11, 2003 2:25 PM
Subject: Mysterious MailScanner hangs


> Hi All,
>
> I have a sporadic problem where MailScanner mysteriously stops picking up
inbound MTA spool files.  A 'service MailScanner restart' temporarily clears
the problem for the most part (inbound MTA queue, normally 0-10, still
hovers between 30-95 afterwards).  When the problem occurs, there is
invariably one MailScanner process taking >90% of the CPU (load usually
1-3), and the problem persists until I intervene (i.e. MailScanner does not
kill and restart itself periodically as it normally does).  I've poked
around the MTA and MailScanner queues, but noticed nothing amiss with any of
the messages (except that some appear never to get processed), nor do any
log entries provide a clue.
>
> At this point I'm trying to decide the next step in troubleshooting;
setting "Debug = yes" in MailScanner.conf merely stops the scanning again,
but I see no output.  Then again I haven't found much documentation on
debugging so perhaps I'm not looking in the right place.
>
> My current setup:
> 6 servers in a DNS round-robin under one hostname (i.e. one hostname
mapping to six different machine IP addresses).
> CPU:            Pentium III / 733 MHz
> RAM:            Two (512MB each), One (256MB), Three (128 MB)
> Distribution:   RedHat 7.3, up2date'd periodically
> MailScanner:    4.20-3
> All six servers run MailScanner + Postfix + McAfee; no spam checking at
this time.
>
> The hardware setup is certainly not ideal, especially where I'm using IDE
drives; I have access to suboptimal hardware, but a lot of it.  It's
actually easier for me to throw a whole box into the mix than to get a
single DIMM > 128MB.  For the most part, the quantity-over-quality strategy
has worked fine, and I've seen this problem occur on all the boxes - again
sporadically - so I don't think the issue is hardware.
>
> Sheer load does not appear to be the issue, either:  a 'service
MailScanner restart' will result in an inbound MTA queue being whittled from
several thousand messages to under 100 in minutes.  We did ramp up a lot of
traffic on these servers on Monday, but the problem did not appear until
Tuesday evening / Wednesday morning.
>
> FWIW we originally saw similar symptoms several weeks ago, back when we
ran ClamAV in conjunction with McAfee, but we discovered that the
clamav-autoupdate was hanging; killing that script caused MailScanner to
wake up with no need for a restart.  I removed clamav from the Virus
Scanners list at that time (I've since seen some postings about this in the
list archives).  When this problem occurs now, I see no update scripts
running.
>
> Any suggestions would be appreciated.  Hopefully I've provided enough info
without being long-winded. :)
>
> Cheers,
> --Eric
>