[SAC] Mailman Postfix tuning - Urgent

[Alex Mandel]

Disk rebuild on osgeo4 is taking longer than expected. Not sure why, but
even with all the VMs off it was going at 2%/hour.

After a couple of hours I turned on Mail so that we wouldn't impact the
mailing lists for too long. The problem here is that Mail is the biggest
i/o user on osgeo4.

Poking around and reading up, I think there are some things that can be
done to make Mail behave better but would really prefer someone who
knows postfix step in and help out here.

Ideas and observations:
Ram-disk for the queues? (Yes we can allocate more ram to the instance)

We seem to have a high deferred queue, do we need to clean out bad
addresses? Perhaps increase the delay time, or spin off the deferred
queue to another "graveyard" server?

Is apache being hammered by bots scanning the archives?

Are there bot like things trying to subscribe, I see some odd @wp.pl
addresses in the apache logs, trying to hit many list in a few seconds
and then rotating the username.

Are we using a local DNS cache?

http://www.postfix.org/QSHAPE_README.html#deferred_queue
http://www.postfix.org/postconf.5.html#queue_run_delay

Who's up for the challenge?

Thanks,
Alex

PS: I'll turn QGIS and Projects back on in a few hours. Hopefully this
can be tuned before that. Adhoc will likely stay off for the weekend.