[Mimedefang] Dramatic Slowdown in SpamAssassin?
stefan at internext.co.za
Mon Aug 27 21:23:28 EDT 2007
I have experienced a sudden significant slowdown in SpamAssassin
processing via MIMEDefang that I would really like to run by the list
membership for opinions.
I have a few boxes configured with MD,SA and ClamAV. On 2 of the boxes,
the SA Scans have suddenly jumped to taking between 6 and 10 seconds.
This is up from the normal scan time of around 0.3 to 2 seconds. The
funny thing is, nothing has changed in terms of hardware or
configuration, and the RAM usage is pretty much the same as it has
always been. CPU usage is higher, but not so that one starts worrying.
More significantly, my sendmail is starting to refuse
messages on too many connections because the emails are taking too long
to process (3 x longer than before).
I have tried multiple things to solve this. First, I have trimmed all my
custom SA rules. Next, since SA uses a lot of DNS-based services, I have
tested this against totally different DNS Servers. I've even upgraded SA
to 3.2.3 and Net::DNS on one of the boxes. None of these seem to make
any real difference, the scan times remain at around 6 seconds for the
What makes these 2 boxes different from others that I have? Well, most
of my boxes are Slackware, but these 2 are CentOS 4. And they are
located in the USA, while my others are in the UK and across Africa. The
CentOS boxes are not on the same network either, so while I could
suspect a networking issue, all other services (like httpd) run 100%
normally. I also have the RAMDisk for /var/spool/MIMEDefang and it seems
to working fine, although it gets a bit fuller with the amount of time
that mails now stay in the RAMdisk.
Has anyone else perhaps experienced something similar, or does anyone
have any additional suggestions on why my SA scan times would suddenly
jump to 3 x their normal duration?
Looking forward to you input.
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