Mail servers

[inx]Olly · 9th May 2008

I'm looking at upgrading our internal systems, and the first thing is mail.

For just our domains / email, I was looking at using a PE 860 Xeon 3060, with RAID 1.

Question for you web hosting gurus, with Spam Assassin running, and all our external email from systems (panel, billing, support etc) would it be advisable to whack 4GB ram in as opposed to the 2GB that's sat in the machine I've earmarked?

Or would it be overkill?

We aren't doing any tremendous amount of mail. It's 99.9% spam!

2GB ram is neither here nor there and I'll probably but 4GB in anyway (unless advised otherwise!)...just interested!

JamieBeeston · 9th May 2008

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see how much ram is used and crucially how much swap is used

if some swap used, upgrade, if alot of swap used, defo upgrade, if none, move along!

Karl · 9th May 2008

Main issue with mail, is i/o. Check the iowait (iostat if linux) and the blk reads and writes.

[inx]Olly · 9th May 2008

Quote:

Originally Posted by JamieBeeston

log in
top
see how much ram is used and crucially how much swap is used

if some swap used, upgrade, if alot of swap used, defo upgrade, if none, move along!

The quoted spec was the *new* spec, J. The mail is running on 3 different servers at the moment, which are all being used for other things, so hard to tell that, sorry!

Quote:

Originally Posted by Karl

Main issue with mail, is i/o. Check the iowait (iostat if linux) and the blk reads and writes.

Thanks Karl I'll bear that in mind

Karl · 9th May 2008

For RAID-1, with SATA drives and a semi decent card, about 1300 block writes per second seems to be the limit.

cookdn · 9th May 2008

Oliver,

I assume for internal purposes you haven't got loads of user mailboxes (mailboxes purposely distinguished from alias addresses)?

Had you considered using a hosted filtering service such as Websense/Opal MailController/MessageLabs? Target price for the service in low volume should be around £27/user mailbox/year.

Filtering of 99.9% spam becomes their problem and your resource requirements for email plummet accordingly.

Best regards.

pipeten · 9th May 2008

I'd definately go with the exta 2GB because it'll cost pittance.

Secondly go with HW RAID1 15K SAS if you can (as mentioned on the IO side).

Then it's down to spam/ham ratio and volume on the proc side of things.

JamesSykes · 12th May 2008

Depends how much mail you are doing. A small dedicated spam filter with 1GB of ram could do 50k/day quite easily and as much as 150-200k/day if the disks are fast enough. (all figures depending on what you are doing to your mail and how)

So in that respect 2GB even could be overkill but for many people it's easier to stick 4GB in and not have to worry about being efficient.

amdcomms · 14th May 2008

Its overkill but id wack in 4GB , least that way things will be fast and you will be able to sleep at night