I keep running out of memory every now and again. What's happening?

Simultaneous Scans

If you're using spamassassin to filter all mail on your domain, you will run out of memory, unless you impose a limit on simultaneous scans.

...

This helps throttle down the load further upstream, and is very beneficial.

Very large mails

You should also ensure you do not scan very large mails, as described in SpamdKillingServer.unmigrated-wiki-markup

Very large mails

You should also avoid using very large custom rules files. The larger custom rules files available from the SA community will exacerbate this problem. A prime example is problem. The following CustomRulesets will kill your server:

• sa-blacklist.cf

...

• or

...

• sa-blacklist-uri.cf
• bigevil.cf

 by Bill Stearns (See [CustomRulesets]). If you haveare memory problems using these rulesets, consider using \[http://wiki.apache.org/spamassassin/SURBL\] instead.

AWL

If you're doing the above and still running out of memory, check the size of your AWL databases. Version 3.0.3 fixes an AWL specific bug that can cause memory bloat from large AWL db files.

You can also use the --clean switch of the tools/check_whitelist utility to remove entries with < n hits, providing a way to clean out the db. This should resolve this specific problem.