[Dovecot] quota calculating
Christian Balzer
chibi at gol.com
Mon Jun 25 17:48:10 EEST 2007
Hello,
On Mon, 25 Jun 2007 10:10:00 -0400 (EDT) "Scott Zahn" <scott at zahna.com>
wrote:
> Currently where I work we use qmail.
My condolences. The worlds most patched PoS (software, really, I
mean software) by the biggest ego in the business.
> Every time a message is
> delivered, qmail seems to walk through the user's entire maildir in
> order to calculate quota usage.
That doesn't seem right, not if it is using maildirsize maildir++
quotas, see:
http://www.inter7.com/courierimap/README.maildirquota.html
The worst case scenario would be a full mailbox, which would trigger
a full recalculation every 15 minutes (Exim does it every 20 minutes).
This recalculation is part of the specification, of course a smartly
designed mail system will (with a few scripts and a database of sorts)
prevent delivery attempts (and thus recalcs) to full mailboxes.
So the first thing to check is if these mailboxes are perma-full
or if they get so much activity that the maildirsize quickly grows
to the 5k size that triggers a recalculation. If neither is the
case, then yes, qmail is your enemy (surprise, surprise).
Or if you are delivering with something else, that is the culprit then.
> Delivering messages simultaneously to
> just a few users who are allowed large maildirs (1-2GB) will bring our
> servers to their knees. Which brings me to dovecot. I use dovecot
> whereever I can, but haven't yet needed to set up quotas. I would like
> to migrate my servers at work to use dovecot, but have a few questions
> regarding quotas. Could someone explain how dovecot calculates quota
> usage on mail delivery? Also, is there anyone here on the list that
> uses quoatas on large maildirs (>=2GB)? How well has it worked for you?
>
Again, having to recalculate the quota eventually is part of the
specification. If your hardware (I/O) can stand the infrequent
recalculations working maildir++ quota requires you are gold.
Regards,
Christian
--
Christian Balzer Network/Systems Engineer NOC
chibi at gol.com Global OnLine Japan/Fusion Network Services
http://www.gol.com/
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