We have two production mailservers running SA spamd. The first handles about 5,000 incoming emails per hour, does spam filtering with SA and virus filtering with qmailscanner and forwards the filtered mail to a server handling the pop accounts. We're using SA 2.64 with Bayes, AWL, Razor and about half of the RBL's. The machine is a 2.8Ghz P4 with 1.0GB RAM and SCSI hard drive. CPU usuage runs between 25-40% and system load runs 1.50 to 2.20 with isolated spikes to 7.0.
The second machine is a 2Ghz Athlon with 1.0GB RAM and an IDE drive. It does spam and virus filtering with SA 2.64 and qmailscanner and also handles POP3 sessions with vpopmail. We use Bayes, AWL, Razor and the same RBL's. It handles approx 2,500 emails per hour (with peaks of 5K emails/hour) and approx 2,000 pop3 sessions per hour (peaks of 5K pops/hour). CPU usage runs about 20% with peaks to 50% and system load averages 0.80 with peaks of 16.0.
We are pretty satisfied with the above setup. We tried moving one of the servers to SA 3.0 in order to use the new MySQL Bayes features but got absolutely killed on CPU usage and system load - that lasted about a day and we reverted to 2.64.
We figure that we'd have to reduce the email load on each server by 50% in order to use SA 3.0 and thereby need twice as many servers. However, we're going to wait until the SA developers take the memory and load issues seriously and fix the problem. Maybe if enough users complain they'll do some high volume production test comparisons of 3.0 with previous versions and sort out the problem.
At 09:33 PM 10/27/2004, email builder wrote:
> email builder wrote: > >>email builder wrote: > >>How much email are you processing ? > > > > > > Well, just the other day we had an average of 48 msgs/min (max 255/min) > get > > run > > through SA. Can't say today yet because can't run our stats tools until > the > > busy hours are over cuz SA is hogging the CPU. ;) > > Hi, > > Your CPU is over loaded. At 48 a minute it should run just ok on a 2.8 > Ghz machine, much over that it's going to start having problems. On our > 2.4 Ghz (not HT) processor if I process over 35 a minute I start having > problems with load.
I have two reactions to this:
1) I like the glimmer of hope and the idea that throwing hardware at the problem can solve it
2) Throwing hardware at problems is usually avoiding fixing the *real* problem. According to other posters on this list, my load is not excessive for a modern-day 2.xGHz machine. I will have to re-read some messages, but I believe responders to my posts on the "[OT] Email Servers" thread quoted similar machine specs and higher load than me and said they did not have load problems. I'd love to hear that I am mistaken and that it's just a matter of too little hardware, but I am skeptical...
> I'd recommend upgrading to a dual server or perhaps putting in a second > server with round robin DNS (or if you can do it, a load balancer).
We've been thinking about a multiple-machine email solution and have been wondering about architecture. Since SA seems to be the *only* email server module that causes us grief (even amavisd-new/clamav is nicer to our machine!!), and although it seems strange not to go with a separate file server or database server machine (or to otherwise split up SMTP and IMAP, etc), I am starting to think (as you suggest) that just adding a separate SA server is going to get us the biggest performance increase. What are people's opinions and experience setting up separate/multiple SA servers? Are there any good links for reading about such setups on the wiki or anywhere else?
> SA is that CPU intensive, it really is. Maybe try adding RBL's in front > of the MTA to reduce the number of messages you have to scan, that's > what we do.
Ha! Yeah, this message rate is *WITH* something like 10 RBL's in Postfix up front. W/out that, we'd *really* be drowning. :)
Many thanks!
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Best Regards,
Jeff Koch
