[Mailman-Users] List performance and server size

Brad Knowles brad at stop.mail-abuse.org
Wed Jul 13 19:02:46 CEST 2005

At 11:03 AM -0500 2005-07-13, Dave Beckstrom wrote:

>  I'm considering Mailman and I have been reading the FAQ and archives in
>  search of an answer to my questions.
>  I didn't have much luck and thought I would ask here.

	Hmm.  That's a bad sign.  Did you search the Mailman FAQ Wizard 
for "performance"?

>  I have a client who needs to send out about 50,000 emails once a month via a
>  one-way list.
>  I'm considering installing Mailman on a Dell server with a 2.8 ghz Xeon
>  processor, 1 GB ram and one 160 GB SATA IDE Hard drive.
>  The OS would be FreeBSD.
>  I'm not terribly strong in 'nix but I do have some experience with OpenBSD
>  and I'm generally good at figuring out new things.
>  Does anyone foresee any performance problems with my configuration?  Will I
>  have a lot of trouble installing Mailman on FreeBSD versus some other OS?

	For large mailing lists, RAM is a critical limiting factor, to a 
point.  Whether or not your system will have enough RAM is hard to 
say.  I'd be inclined to start with more, if possible.

	But it may turn out that you don't need all that RAM.  This is 
one of those things where you take a guess (and you usually try to 
guess conservatively), and if things are obviously too bad then you 
revise the system configuration upward from there.

	After RAM, the next most important limiting factor is the disk 
I/O subsystem.

	On a busy server, ATA or EIDE drives do not cut the mustard -- 
not even SATA is good enough.  You need SCSI.  Not even with an 
intelligent drive controller will ATA or EIDE cut the mustard -- you 
need SCSI.  An intelligent SCSI controller will be an improvement 
over standard SCSI drives, especially if you can configure it for a 
large amount of battery-backed write-back cache, and the drive array 
itself in a striped/striped or "plaid" RAID-1+0 configuration.

	The only question here is whether or not your system will be so 
busy that the ATA drives hurt you by so much that you are forced to 
replace them.  It's impossible to answer that question a priori -- 
you may have to try it and find out.

	If at all possible, I would recommend replacing the drives in 
this configuration with SCSI, but that may not be possible.

	You're also going to need an improved filesystem, and FreeBSD is 
a good choice here, with more recent versions having "soft updates" 
enabled by default.

	You also need an MTA configured for maximum performance.  It is 
possible to configure sendmail to extremely high levels of 
performance, but it takes a lot of work to do, and takes a fair 
amount of management to keep it there.  Postfix works pretty well 
out-of-the-box for small to medium size lists, and there are a lot of 
knobs you can tune for further performance on larger lists.

	Operating system wise, I believe that FreeBSD is a good choice. 
It is my preferred choice, but of course that's a personal preference.

	One thing you generally don't need on a large mailing list server 
is CPU.  Boxes with very slow CPUs but well-designed I/O subsystems 
will run circles around boxes with much faster CPUs but less well 
designed I/O subsystems.

	The problem is that pretty much all this information is already 
in the FAQ, with further information in the archives.  So, if you 
searched for "performance" and you didn't find it then there is a 
bigger problem.

Brad Knowles, <brad at stop.mail-abuse.org>

"Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety."

     -- Benjamin Franklin (1706-1790), reply of the Pennsylvania
     Assembly to the Governor, November 11, 1755

   SAGE member since 1995.  See <http://www.sage.org/> for more info.

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