Any one else notice...
fizz at BOMB.NET
Fri May 31 21:18:28 IST 2002
unfortunatly were already running a name server on the same machine, and
have 512megs ram in it. Its only a p3 500, but it was keeping up with the
load great before. I have my sendmail set to do rbl checks, i have spam
assassin's user_prefs set with skip_rbl_checks 1 and ignore_rbl_checks 1 and
commented the rbl checks out in mailscanner (this is how i was running
already) Something changed in the code in the last release or so which
changed some timing. Julian mentioned to me that spam checking is now done
on seprate forks (seprate processes) and hes not sure if thats where the
bottleneck is. Although i did some testing with spam checks = no and it
improved a little but not as much as it should. In version 3.13-2 witrh spam
checks off i can process 2000 messages in like 5 minutes, or less. with the
new version it took well over 15 minutes.
Just some more information for you guys.
----- Original Message -----
From: "Jeff A. Earickson" <jaearick at COLBY.EDU>
To: <MAILSCANNER at JISCMAIL.AC.UK>
Sent: Friday, May 31, 2002 3:49 PM
Subject: Re: Any one else notice...
> I'll weigh in on this thread too. Last Monday, I moved our mail
> to a Sun E220R, 2 cpus, running Solaris 8. I'm running mailscanner with
> spamassassin turned on. I have all of the "Spam List" options in
> mailscanner.conf commented out. I have Spamcop assigned a non-zero score
> in spamassassin, so I hope/think SA is using spamcop (I'm not sure yet).
> We use RBL+ in sendmail, and we subscribe to it transfer mode, so RBL+
> mail gets rejected before getting to mailscanner. I have the delivery
> mode in mailscanner set to "queue". We use Sophos. We process roughly
> 20K messages a day. Result: the system works great, no slowdowns, no
> clogged queues, nothing but bliss. Julian should be knighted, IMHO.
> Most of what I see in this thread sounds like DNS slowdowns. Here's
> my advice:
> * run a modern version bind on your mail server, at least in caching
> to handle the DNS lookups for you. If you use RBL+ or other
> mode DNS blocklists, do the zone transfers to the mail server, so
> DNS queries never leave the box for RBL+. You will probably have to
> pay money to get zone transfers. As a part of running bind on your
> server, make sure /etc/resolv.conf is configured so that the first
> is the external interface (not loopback) of the mail server. Here is
> resolv.conf for my server, emerald:
> domain colby.edu
> nameserver 188.8.131.52 # emerald, this host, not loopback -- for RBL+
> nameserver 184.108.40.206 # opal
> nameserver 220.127.116.11 # ruby
> nameserver 18.104.22.168 # polar.bowdoin.edu
> nameserver 22.214.171.124 # ns.cw.net
> Any DNS lookup on emerald goes to the local cache first, then other
> local machines, then remotely.
> * Have lots of memory in the machine for named to use. Named is using
> about 140 MB of resident memory on my machine right now. If you are
> using bind 9.X (you should be) and have a multi-cpu machine, let bind
> run threads on all cpus.
> * If you are doing DNS spam-blocking, do it in sendmail. Reject the
> stuff before it gets to mailscanner or spamassassin.
> * Comment out some the "Spam List" lookups in mailscanner and see if
> that helps. Fewer DNS lookups, especially to a remote site that is
> overloaded (like relays.ordb.org perhaps), may be a bottleneck.
> check the config for SA and try to control DNS lookups there too.
> * If you are running Solaris, shut off nscd!! This code is a real
> DNS bottleneck for a system doing beaucoup lookups. When we first
> moved our Apache web server to Sun, we were getting glacial response
> times to webpage requests. I found a technote at the Apache site
> nscd problems. Turned it off, and things ran fast after that.
> The same advice applies to other Solaris apps doing massive DNS,
> and nscd could appear on other versions of UNIX. Let bind do the
> work instead.
> Of course our students are gone right now. The system could blow up when
> they return next Fall.
> ** Jeff A. Earickson, Ph.D PHONE: 207-872-3659
> ** Senior UNIX Sysadmin, Information Technology EMAIL:
jaearick at colby.edu
> ** Colby College, 4214 Mayflower Hill, FAX: 207-872-3076
> ** Waterville ME, 04901-8842
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