[Mimedefang] performance tuning once again
tomvo at absi.be
tomvo at absi.be
Sun Oct 16 11:40:22 EDT 2005
Hi David,
I just got a hunch: i checked the /var/spool/MIMEDefang directory, looked
which directories weren't being removed after 2 minutes, and did a fuser
of those.
and sure enough, processing occupying these directories were invariably
python processes. I had problems before with lingering python processes,
but never made the link with these timeout's.
I've restarted now with pyzor disabled, and so far i didn't see any new
errors (before, i had them almost every 5 minutes).
So I guess (fingers crossed !) that this was my problem, and all my
tinkering with mimedefang parameters didn't make any difference at all.
thanks for your input though,
regards,
tom.
---------------------------------------------------------------------------
Tom Van Overbeke - ABSI Unix System Engineer
email: tomvo at absi.be
Tel: +32 2 333 40 00 - Fax: +32 2 332 34 69
website: http://www.absi.be
---------------------------------------------------------------------------
"David F. Skoll" <dfs at roaringpenguin.com>
Sent by: mimedefang-bounces at lists.roaringpenguin.com
16/10/2005 16:40
Please respond to mimedefang
To: mimedefang at lists.roaringpenguin.com
cc:
Subject: Re: [Mimedefang] performance tuning once again
tomvo at absi.be wrote:
> if the output of "md-mx-ctrl histo " command on the busiest time of the
> day shows that let's half of the slaves have 0 messages scanned, does
this
> mean that i can safely lower (MX_MAXIMUM parameter)
Yes, probably. But there's almost no benefit to lowering MX_MAXIMUM.
You should set MX_MAXIMUM so that if it's ever reached, your machine does
not swap. If fewer than MX_MAXIMUM slaves are required, the multiplexor
won't start them. (It only keeps MX_MINIMUM slaves around at all times.)
> I have implemented the following 'performance improving' features:
> - /var/spool/MIMEDefang on a ram disk
> - MX_EMBED_PERL=yes
> - spamassassin only checks message of <100K
Those are all good.
> I am also using the multiplexor queuing using these parameters:
> # Multiplexor queue size -- default is 0 (no queueing)
> MX_QUEUE_SIZE=100
That's probably way too high. If most of the time, you have fewer than
MX_MAXIMUM slaves, nothing will get queued anyway.
> My main concern is that every know and then,i get these dreaded 'timeout
> before data read' errors (timeout of 10 minutes specified in
sendmail.cf)
That's weird. It shouldn't be happening.
> # Number of seconds a process is allowed to scan an email before it is
> # considered dead. The default is 30 seconds; we suggest 600.
> MX_BUSY=600
> What happens if this limit is exceeded ?
The multiplexor kills the slave and returns "please try again".
> I would like to configure my mail relay in such a way that,
> when for some reason, the mail couldn't be scanned in time, the mail is
> accepted anyway (because we have user's dropping mail directly to the
mail
> relay from their mail client's, and if they receive such a 'please try
> again later' error, they get annoyed.
It's a bad idea to have mail clients connect directly to a machine running
MIMEDefang; best to have a dedicated mail-accepting machine that then
relays
to the MIMEDefang machine. Even if you could configure the machine to
accept
mail in the event of a busy timeout, I think a 10-minute wait for the mail
server to respond would be pretty annoying. :-)
Regards,
David.
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