MS performance as a gateway comments

[Martin Hepworth]

Alan

your specs and message flow don't seem to match the other high end boxes
(ie you system should be able to handle well over a million messages aday).

what extra SA rules are you running? I wonder if some of the larger ones
are causing problems (not to mention the RBLs - are you running a local
caching nameserver on t he box0?


--
Martin Hepworth
Snr Systems Administrator
Solid State Logic
Tel: +44 (0)1865 842300


Alan wrote:
> This is just some of the things I have experienced over the last year
> related to performance. FWIW, maybe it will help someone down the line...
>
> I have been running MS/SA for about a year now, and have been struggling
> with performance issues since day one. Over this time, many of you have
> greatly helped me in my tweaking, including:
>
> tempfs for working dir
> seperate scsi drive for queue partition
> reiserfs for queue fs
> dual pent 4 with 2 gig ram
> minimal logging
> smaller batch size (20)
>
> In my configuration, I have 4 smtp servers receiving email from the outside
> world. Each of these 4 servers route the mail they accept directly to my
> MS/SA server for spam/virus/exploit filtering. Everything that is passed by
> MS/SA is then finally sent on to a final smtp server where the inboxes
> reside. So you can see that my MS/SA server acts as a gateway; it accepts
> no email directly from the outside world, and it has no inboxes on it.
> About 300,000 emails per day enter the MS/SA server, and its filtering out
> about 72% of that volume, passing the rest on to my users.
>
> In my original install, I was using sendmail as the MTA. During much of the
> day, so many MTAs were running that server load would hover around 14-20.
> During quieter times, it would drop to maybe 5-7, never below. If I
> configured sendmail to limit MTAs, I would have backups on the 4 incoming
> smtp servers as they could not deliver their queues to the MS/SA server
> fast enough, and/or there would be backups in the delivery queue of the
> MS/SA server itself as there were not enough MTAs available for final
> delivery to the inbox server. If I ran enough MTAs to handle incoming and
> outgoing traffic, load would be so high that MS became the bottle neck.
>
> Bayes tests were out of the question due to load, and various network tests
> (razor2, surbl etc.) often had to be disabled when back logs were bad. It
> was not uncommon each day to have 20,000 messages waiting to be processed.
> During daily heavy load, the time from when an email hit my first server
> until it was dropped into the user's inbox would be 4-7 hours.
>
> A couple of months ago I replaced sendmail as the MTA with exim. I really
> liked exim's configuration flexability and features, and was quickly able
> to get some neat tweaks running. I found that each exim MTA seemed to use
> less resources than each sendmail MTA had used, and I was able to keep
> network tests running much more often. It was an improvement, but loads
> were still usually above 8 and total delivery time was still poor,
> sometimes as high as 2 hours during the day.
>
> Now I have replaced exim with zmailer, and all I can say is WOW! First,
> zmailer reuses the same tcp/ip connection to my final inbox server for as
> long as there are messages in the delivery queue to be delivered. This
> means there is never more than a single MTA running to deliver messages.
> Secondly, the zmailer smtpserver process that receives incoming messages
> from my 4 smtp servers, along with the zmailer smtp process that delivers
> filtered messages to my inbox server all use minimal system resources.
>
> Since switching to zmailer as my MTA, system load is averaging under 4, and
> very few peaks above 5, and they are very short. Pre-filtered queue size
> has yet to go over 100 during peak hours, as opposed to previous queue
> sizes of over 10,000. Delivery queue size is likewise low, typically under
> 50. Delivery time from initial reception to user inbox is now down to 3
> minutes or so.
>
> So, if you are struggling with system load and bottlenecks as I have been,
> and have made all the hardware tweaks you can think of, I HIGHLY recommend
> you try zmailer as your MTA.
>
> ------------------------ MailScanner list ------------------------
> To unsubscribe, email jiscmail at jiscmail.ac.uk with the words:
> 'leave mailscanner' in the body of the email.
> Before posting, read the MAQ (http://www.mailscanner.biz/maq/) and
> the archives (http://www.jiscmail.ac.uk/lists/mailscanner.html).

**********************************************************************

This email and any files transmitted with it are confidential and
intended solely for the use of the individual or entity to whom they
are addressed. If you have received this email in error please notify
the system manager.

This footnote confirms that this email message has been swept
for the presence of computer viruses and is believed to be clean.

**********************************************************************

------------------------ MailScanner list ------------------------
To unsubscribe, email jiscmail at jiscmail.ac.uk with the words:
'leave mailscanner' in the body of the email.
Before posting, read the MAQ (http://www.mailscanner.biz/maq/) and
the archives (http://www.jiscmail.ac.uk/lists/mailscanner.html).