----- Original Message -----
From: "Ralf Hildebrandt" <ralf.hildebra...@charite.de>
To: <postfix-users@postfix.org>
Sent: Friday, March 20, 2009 6:52 AM
Subject: Re: Performance tuning
* Brandon Hilkert <bhilk...@vt.edu>:
We send out a pretty volume of emails right now using a combination of
SQL and IIS SMTP. We get rates now of about 5,000/min. We're looking to
not only improve the rates, but incorporate DKIM/Domainkey signing into
the process. The choice has been made to go with postfix along with a
queue directory on an XFS file system.
You can check if the disk I/O is the bottleneck by simply putting the
queue fs in a RAM disk!
Sorry if this is a stupid question, but how do I go about this. I tried:
mkdir /ram
mount -t ramfs none /ram
and when I send a mail, postfix says there's not enough space in the queue.
Should I be doing it a different way?
I also put the queue directory back on an ext3 partition and the rates went
up by about a factor of two.
Also, by default the syslog messages were already set with
" -/var/log/mail.log". I disabled mail logging all together and found no
change in rates.
My disk is writing about 3 MB/s which should be well within it's range. I
would hope even larger, but I would like to work out the ramfs and test for
sure.
I'm using postfix as a relay, and having it sign the outgoing emails
with DKIM. That process was about twice as slow as without it. Without
DKIM, I'm getting a rate of 700/min.
Signing takes time! htop will tell you IO rates and CPU usage...
--
Ralf Hildebrandt
Postfix - Einrichtung, Betrieb und Wartung Tel. +49 (0)30-450
570-155
http://www.computerbeschimpfung.de
"Windows 95 /n./ 32 bit extensions and a graphical shell for a 16 bit
patch to an 8 bit operating system originally coded for a 4 bit
microprocessor, written by a 2 bit company that can't stand 1 bit of
competition."
