[CentOS] Planning Mail Server (with low resources)

[Rodrigo Barbosa]

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On Tue, Dec 06, 2005 at 03:56:50AM +0000, Karanbir Singh wrote:
> >First off, dump either antivirus or antispam on that machine. You
> >don't have enough memory to keep both happy.
> 
> How about using MailScanner ? and wrap that around clamav + 
> spamassassin, you can run it with 2 - 4 threads on a machine with 
> 256megs of ram, and since spamassassin runs via its perl interface 
> locally ( and not via spamd ), it uses up no resources while its not 
> running.

Yeah, that will work for a month or 2. After than, the bayesian database
will start to get huge, and spamassassin will take a lot of time to
start and use a lot of memory.

> MailScanner might slow your inbound mail queue processing by a few 
> seconds, but would allow you to better manage the resources you have on 
> the machine ( and also implement any policy based email rules you might 
> want to have )

After 2 months, on a 256M machine, spamassassin alone can slow a single
e-mail by up to 2 minutes. Which can lead to a nice snowball issue.

> >A P3 1.4GHz is more than up to the task, so you will have no problem there.
> >
> >You might also want to change Cyrus-imapd to something simpler, like
> >wu-imapd, since it should take less resources from the machine. Then again,
> >I have very little experience with cyrus, since I either use wu or 
> >courrier.
> 
> With 2000 users and 80+ concurrent users, you will find Cyrus performs 
> faster with lower system resources than Wu-imap or Dovecot!
> 
> Also, on a machine with that setup, I'd have a Gig of Swap. And that 
> 40GB hdd, i wonder how fast that runs :) might end up being the bottle 
> neck in the equation.

The main tip would be to have the swap partition close to the middle
of the disk, so you can reduce the disk head seek time. At least in
theory, considering there is no sector realocation due to bad blocks.

- -- 
Rodrigo Barbosa <rodrigob at suespammers.org>
"Quid quid Latine dictum sit, altum viditur"
"Be excellent to each other ..." - Bill & Ted (Wyld Stallyns)

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