After my recent issues with maildrop and delivering mail, I got to know my system a little better. Having scanned through the qmail-queue I noticed a lot of messages just sitting around for days on end trying to deliver to non-existent email boxes, in response to spammers. Some of my bigger customers had all email set to 'bounce' and not 'delete'.
Several hundred e-mail accounts getting several thousand spams a day ended up creating a constant flow of between 10,000 and 20,000 mail messages "bouncing" in the qmail-queue on a daily basis. I was getting pretty worried about the hard disks that contain my mail queue and the /var/vpopmail/domains tree. They were dishing out between 250 - 400 (I've seen it as high as 800) transactions per second on average. After setting vdelivermail delete on some of my bigger domains, my queue has dropped to under 1000 messages, and iostat shows a SIGNIFICANT decrease in disk activity during both peak and off-peak times. I wish someone had told me about that earlier. What a great tool for reducing unnecessary load. !DSPAM:477e0c4c310541912799895!
