Running amavisd-new on MX hosts?

[Rich Wales]

Hi.  I would like to hear other people's thoughts on a possible way to
improve my current e-mail spam filtering setup.

I am using Postfix, SpamAssassin, and amavisd-new on my mail server.  My
mail server doesn't take incoming mail directly; rather, I have two MX
hosts, which currently accept incoming mail and forward it directly to
my mail server.  The MX hosts do DNSBL blacklisting, but they don't do
any content-based filtering (that gets done on the mail server).

I'm considering the idea of moving SpamAssassin and amavisd-new to my MX
forwarders, so that spam would be quarantined on the MX hosts and not
sent to my mail server to be detected and quarantined there.  One
possible downside to this which I can imagine is that I might need to
deal with two separate spam quarantine databases (one for each MX host),
rather than a single quarantine database on the mail server -- any ideas
on how to avoid or deal with this?

Rich Wales
richw at richw.org