= What kind of servers do I need to run SpamAssassin for my large site? =

Obviously, every site is different.  Here are some details on one large scale deployment that you may find useful as a benchmark.

[[http://www.mweb.co.za|MWEB]] is the largest ISP in South Africa, with approximately 350,000 mailboxes, all of which get filtered through SpamAssassin.

Their setup entails 8 servers running Postfix, 12 servers running [[http://www.ijs.si/software/amavisd/|amavisd-new]], and an additional 5 servers running Trend Micro and Vexira anti-virus.  Their 25 servers are Dell Power Edge 2650's with dual 3.0 GHz Xeons, 4 gigs of ram, and 5 SCSI drives in a  RAID 10 configuration (1 hotspare).  They're running a custom built Fedora Core 2, 2.6.7 kernel .

Here are their statistics for April:

{{{
Year  Month Messages Blocked  Messages Passed  Total Messages  Percentage Blocked 
2004   Apr     106,710,305     25,065,604       131,775,909         80.98 % 
}}}

Thus, their long term average is 131,775,909 / 30 / 24 / 60 / 60 = 50 messages per second.  Their peak rate is up to about 300 messages a second, or 6x their average.

Note that while amavisd calls Mail::SpamAssassin directly, it runs Perl as a daemon and should offer performance quite close to spamd.  This suggests that a single brawny server running spamd can comfortably handle 5 messages a second and may peak up to 30 messages per second.

= More info =

Please contribute details on your large installation.  It's fine to do so anonymously if necessary.

= Contributors =

 * DanKohn interviewing camis at mweb.co.za