Mailscanner and server load

[David J. Duffner - NWCWEB.com]

>-----Original Message-----
>From: MailScanner mailing list 
>[mailto:MAILSCANNER at JISCMAIL.AC.UK] On Behalf Of kfliong
>Sent: Wednesday, August 25, 2004 10:14 PM
>To: MAILSCANNER at JISCMAIL.AC.UK
>Subject: Mailscanner and server load
>
>
>Hi,
>
>Okay, I know the question about mailscanner and server load has been
>discussed before but i this seems to be a little different.
>
>My server specs is as below :
>
>Celeron 1.3GHz, 512MB RAM, 60GB HDD, Redhat Linux 7.3, Ensim Pro 3.5.23
>
>MailScanner 4.32.5-1
>SpamAssassin 2.64
>MySql 3.23.58
>ClamAV 0.75
>MailWatch 0.5.1
>sendmail as MTA
>
>The problem is that after updating the packages, my server's 
>load is very high. Before that it was around 3.5. After upgrade, it ran up 
>to above 30 for few 30 minutes before coming back down to around 3.0 now. 
>I have not enabled SURBL yet. But the only reason i upgraded is to use 
>SURBL. But now, since the load is kinda high, I am afraid to run SURBL (with 
>SpamCopURI) which would definitely increase the load. I do not run DNS 
>server locally. I am resolving DNS using my webhost's. Would that increase the 
>load if I run SURBL?

        First, if you're where I think you are with hosting for this
box then I can see a few issues you can clear up right away:

        #1 - take the plunge and upgrade to Ensim Pro 4.XX on either
RHEL or Fedora Core 1.  Sucker will run MUCH smoother with that
upgrade and it's all free for the taking from Ensim.  We had a few
issues with 3.5.XX that went away with the in-box upgrade for 3.7
and went out the door completely when taking it up to 4.XX on FC1.
Many will suggest RHEL, in hindsight we'd have probably gone that
route so it's your option.  ALWAYS do the Standalone, don't touch
the ServerAdvantage (or whatever they call it) from Ensim as that's
still buggy as all getout.

        #2 - running a virtual copy of that machine with the upgrades
mentioned, but it came from where you were.  Some modules even later
versions than you show.

        #3 - DON'T PANIC on load averages.  We're using MRTG and MailScanner
MRTG and they don't agree with load averages, so you're not seeing a
realtime accurate report!  We went into panic mode, turned out the
reason you see those as 'averages' is that it's spiking MailScanner
every so often, but the sampling rate in straight MRTG is taking
those little spikes as gospel and giving you the false info.  Sit
and watch 'top' for awhile and you'll see the pattern emerge.

        There are others here who may have suggestions to tweak those
spikes down a little, that can't hurt.  But overall you're seeing
an illusion, we finally got a grip on it as MailScanner MRTG samples
at a different rate and is giving us a REAL average to work with on
loads.  Straight MRTG has some other reporting issues we're trying
to work out, but it's seconds from getting stripped off the boxes
rather than waste time on it.

        #4 - We're running 5 sources in MailScanner without any issues,
so adding SURBL shouldn't cause you pain!

        #5 - MailWatch, if you have it working 100%, will most likely
need attention if you upgrade Ensim Pro.  We installed it after going
up to 3.7.XX and it's not working as well as we'd like but does do 
the basic job we require of it.  Tons of posts in the forum for your
Host on this one...

>My question is, what can I do to lower the load? How much load would it
>reduce if I upgrade to 1GB RAM?

        Load - slight tweaking but again it's an illusion.

        RAM - Hey, we all could use more RAM, never hurts to bump it
up but in this case it's not the cure as you're getting data the CPU's
overloading (which it's not at a rate to panic about) and the RAM 
really has no bearing on improving that, just gives more room for
additional processes to run which will tax the system if you turn
things like copies of MailScanner (concurrent) up.  Save the $$, stay
at 512MB unless you see a real reason or someone here thinks it's an
absolute requirement to do so.

>What if I get another server dedicated in handling mails? This 
>server would be used for websites. How would things work if I have 2 server?
Anyone
>would give a simple guild to doing this? I know I would then 
>need to run a DNS server which would route MX records to the 2nd server, right?

        All possible, all do-able, posts galore in Ensim's forums and
your Host's (if I'm guess right) forums as well.  Again, never hurts
but you're seeing a problem that doesn't exist.  If you host over 50
domains on that box, then some tweaks need to come into play and 
using a second server wouldn't hurt.  But again, why pay for it if
it's not a requirement.

        If you're where I think you are with Hosting, we abandoned
their DNS services quite some time ago.  Just one more useless
hop and the Ensim Pro setup is more than capable of handling the
DNS job with ease, even on the Celeron's.  We do it all in each
box, never had issues, it sends out DNS records on a regular basis
and it works like a champ.  Updates happen as soon as you do them,
whereas the Host's DNS servers have a notorious schedule.  Also 
factor they have hosted some serious spam and intrusion attempt
folks and their DNS domains aren't favored by some other servers,
so your updates may not get out as fast as doing it direct on your
boxes.  Since it comes right from you, unless you do something to
get blacklisted you're in the clear so that anyone trying to get
to your hosted sites actually makes it in short order vs. 404's.

        I know there's a ton in this post, but we've been there and
done that here so I understand your concerns.  Feel free to hit me
offlist if you want to compare notes, we can toss you towards a
few excellent resource folks out and about that know Ensim far 
better than we ever will!

      David J. Duffner
      VP Operations
      NWC Corporation
      NWCWEB.com
      
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