Amavis stalling on large emails

[Mark Martinec via amavis-users]

> Using postfix, amavis, spamd, clamav.
> I recently migrated to a new server.  Configuration is the same but 
> latest versions
> of all software.  Postfix allows 50MB emails.  Amavais 
> sa_body_size_limit is 200*1024.
> I have some 4 stuck in the postfix queue, timing out (1800 sec 
> timeout).
> These emails are all > 30MB.
> What should I be looking for? Obviously it shouldn't be passing to SA 
> at that size.
> Could clamd be taking that long?  If so, how do I address that?

A 30+ MB message could indeed be taking a long time to process,
either in a virus scanner or while decoding highly compressed
archives with lots of files - although 30 minutes seems way too high.

Assuming that mail processing did complete eventually (just postfix
timing out meanwhile), there should be a timing report in the log
at log level 2 or higher, it should give some indication on
what is taking so long. If not, try (temporarily) increasing
the log level and flush the postfix queue, to be able to see how
operations are progressing in amavisd on such problematic message.

   Mark