Monthly Archives: December 2006

E-mail Week

It’s been the week of e-mail, and by that I mean helping people with their e-mail and their e-mail servers. It’s been a challenge switching gears between nullmailer, sendmail, postfix, and qmail all week long. “Okay, which server is this again?” As I write this, I have three ssh sessions open to three different servers running three different MTAs, troubleshooting different problems with each.

Some of it has been explaining to people about e-mail, MX records, outgoing versus incoming e-mail but then there’s been interesting problems like trying to balance a heavily-loaded, lightly-resourced server running Postfix/MailScanner/Clam/SpamAssassin front-ending for a Sendmail server, dequeuing tens of thousands of e-mails, of course all while trying not to overload the either server. So far I have the MailScanner server processing happily with a load average of 11.61, 11.73, 12.10 while the sendmail server is running at 9.76, 6.19, 7.48 and spiking as high as I let it with the load average controls. Just when I think I can increase the concurrency and throw more at the sendmail server the load spikes, as if to plead with me to not give it any more right now.

Postfix’s qshape has been my friend on the Mailscanner server since running mailq on a heavily loaded server is somewhat an exercise in futility. I’m a firm believer in Postfix but not so much as to refuse to work on qmail and sendmail servers. Postfix has excellent documentation, sane configuration options/syntax, and plays well with others. Here’s an example of good documentation: