Recently I installed five machines with SpamAssassin (spamd) and use the DNS round robin method to do dumb load balancing between them.
I finally finished altering all my users' .procmailrc files to include the '-d hostname.tld' argument to spamc so that they would use one of these 5 machines. Over this last weekend we experienced a huge influx of spam late at night. We had nearly 14,000 SMTP connections in a single hour. Most of these were rejected due to either of 'User unknown' or 'Domain of sender address <> does not resolve|exist'. But each of the remaining messages all needed to be piped through one of the 5 spamds. At some point one of these spamds became wedged. Many spamcs finally gave up attempting to connect to spamd due to this wedged spamd. What do others do to create fault tolerance in their spamassassin installations? - Mike
