On Tue, 13 Jul 2004 14:28:34 +0200 fil <fil@rezo.net> wrote:

...

I ask because Chuq Von Rospach has done some calculations on what should theoretically happen to your performance if you enable VERP, but I don't know of anyone who has actually timed the performance difference on large lists.

Usually the sending (mailman to postfix to 90% of users) takes a bit more than two hours ; yesterday it took about 6 hours.

That's an effective delivery rate of ~1,300 deliveries per minute, which is fairly low assuming moderate hardware.

ObNote: I found I could sustain 2,400 deliveries per minute with a quick-poke tuned Postfix on a 512Meg RAM PII-333 with separate spindles for spool and log. Some minor efforts at more disciplined tuning suggested that it could sustain 2,800+, but I could never verify that as I just couldn't keep the spool fed fast enough.

But more importantly, the Mailman -> postfix thing took 5 hours instead of ~ 15 minutes.

What system metrics spiked during this time? 160K/5 hours is a delivery rate of less than 600 per minute. That's one message every 10+ seconds which is quite slow. Even if you double that (receipt and transmission) that's only 1,200 per minute which is still dawdling territory. Your MTA should have been able to keep that spool empty while twiddling its thumbs.

-- J C Lawrence ---------(*) Satan, oscillate my metallic sonatas. claw@kanga.nu He lived as a devil, eh? http://www.kanga.nu/~claw/ Evil is a name of a foeman, as I live.