hardware sizing for a large mail installation?

Oliver Falk oliver at linux-kernel.at
Thu Sep 30 10:55:56 EDT 2004

> > Someone on the linuxmanagers list suggested I post my 
> > question here, so here goes:
> >
> > I'm looking for pointers (past experience in particular) 
> > for sizing a mail
> > server for a large-ish mail install based on postfix, cyrus, 
> > amavisd-new,
> > clamav, spamassassin, and web mail (most likely imp) serving around 
> > 100k
> > mailboxes.  I estimate I'll need to be able to pass through 
> > the whole
> > chain around 40msgs/sec continuously to be on the safe side.  If 
> > possible,
> > I'd like to do this on a single server.  Cyrus murder 
> > probably isn't an
> > option, but I think I could swing a separate box to do the content
> > filtering.  Would, say, a 4-cpu Xeon with ~8GB RAM suffice for the
> > MTA/IMAP combination?
> I/O, I/O, I/O -- it's off to work we go!!
> mail systems need primarily disk bandwidth. Get a killer disk 
> array (fibre-channel or SCSI) and that will keep you happy. 
> The Xeon is nice, but it's disk bandwidth you *need*. I can 
> recommend the StorageTek D-series disk systems, but a bit expensive.

That's not fully correct. Yes, it's true that mail systems need
primarily disk bandwith. But if you run - as he pointed out he will -
spamassassin, amavisd, clamav and so on, you will also need a lot of CPU
power and Memory, especially if you have many users who get a lot of

My setup for about 1200 users (~ 60000 - 70000 mails/day):
* Some IBM machine
* 2 GB RAM
* Dual-Xeon (2.66 GHz)
* 100 GB Harddisk (SCSI 5 with IBM ServeRAID Controller)

That setup is OK, but there's allready more memory and larger hardisks
on our wishlist. :-)


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