Matt Cramer wrote:
Forrest, let me add some "numbers" to Matt's point.
[cut]We move about 2 million emails inbound/month, and 1 million outbound/month. Our MTAs are 3 linux boxes running sendmail, and pass emails into our internal mail system which stores user mailboxes (about 15000). Each MTA runs MIMEDefang and SpamAssassin. Each box does a
We do NO scanning of outbound mail. Virus scanning is handled by the internal mail system, as we have not yet needed to do virus scanning on the Internet MTAs.
[cut]
We run a "front-line" Postfix+Spamassassin SMTP farm that accepts incoming mail from Internet. Intra-ISP (yep, we're an ISP) mail doesn't get antispam filtering. The inbound SMTP chain is completed with an antivirus farm.
Both AntiSpam and AntiVirus gateways are under hardware load balancing, and are composed of two identical servers.
As of yesterday (March 3rd, 2004), on one of the two servers:
Postfix Summary
Inbound Msgs 44012 Inbound Size 1586 Mbyte ---------------------
Clean Msgs Summary
Clean Msgs 15416 Size 258 Mbytes Proc Time 2402 seconds ---------------------
Spam Summary
Spam Msgs 12058 Size 102 Mbytes Proc Time 1543 seconds
As a matter of reference, our AntiSpam machines are IBM xSeries 345:
1st) 2xXeon @ 2.4GHz, 1GB RAM, 200MHz bus 2nd) 2xXeon @ 2.8 GHz, 1 GB RAM, 400 MHz bus
both running untuned Linux 2.4 kernel, Spamassassin 2.62 with two custom rules, threshold at 3.5, no analysis of >150k mails.
During worktime hours (8-18 local) the load on the first machine is around 2, on the second machine is way below 1.
Bayes DB is on each single machine and we do training sessions on both servers, when needed. Sharing the Bayes DB between multiple SpamAssassin servers can be achieved using a RDBMS as a backend, but this adds another point-of-failure. Hardware load balancing does a good job in presenting all servers the same incoming spam-base.
Number of managed domains doesn't really matter until there's no per-domain AntiSpam customization.
If anyone would like to have more numbers, just ask and I'll do my best to produce some statistics.
Paolo Cravero
