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Re: New Mailserver...

On Mon, Jan 07, 2008 at 12:58:33PM +0100, Michelle Konzack wrote:
> It was an AMD Sempron 2200+ with 1 GByte of memory, an older AMI Megaraid
> Enterprise 1200 (with one Raid-1 + Hotfix using three DDRS-39130 for OS
> and one Raid-5 for the Mailstorage using five 18 GByte IBM disks)
> Currently I am using a reserve mainboard (P2/366/512) which can not
> handel more then 5000 messages per day...  :-/
> Now I want to rebuild the Server from scratch using Etch with the courier
> suite, fetchmail, procmail, clamav-ng, spamassassin, apache2 and php.
> I like to continue using SCSI drives (or maybe WD Raptor SATA) since I
> have had a very negative experience using PATA disks for a courier server
> because the traffic produced by the maildir is realy heavy for the disks.

i doubt if that's really the case. i'm sure it happened, i just think
you've misdiagnosed the cause.  40K msgs/day is NOT a large load, it's
not even remotely close to a heavy mail load.

i'd guess you had insufficient memory (spamassassin uses heaps of RAM -
it's a pig) for disk buffering, thus slowing all disk I/O.

i've run much larger mail loads on much smaller systems, with much less
memory. e.g. a fairly active mailing list with over 150,000 subscribers
on an old pentium with 64MB RAM (it died under the load with sendmail,
but worked beautifully with postfix). i don't remember exactly when we
did it, but we later upgraded that box to a PII with 512MB, sometime
before the subscriber base got to about 500,000. it was a very popular
computer games related mailing list.

hmmm. i just had a thought. if you were running the IDE drives with
software raid-5 and comparing them to SCSI drives with hardware raid-5
WITH a non-volatile write cache, then that could cause significant I/O
load problems. raid-5 write performance really sucks - to the point
where it is almost unusable unless you have a large NV write cache. if
that's the case then forget what i said above about misdiagnosing the

> Since the Mailserver is my dedicated @home Mailserver which do automated
> mail-processing (arround 40000 messages per day but maybe increasing
> specialy by spam attacs) I like to go as cheap as possibel but want to
> have enough reserves in case of problems like spam.
> My preference is on AMD 64bit CPU's (I think, the programs above should
> not have anny problems with amd64) and I like to know, what you can
> suggest.

amd64 is fine.  i run several amd64 boxes, some with 32-bit debian (i386
binaries), and some with 64-bit debian (amd64 binaries).  the only
things that have problems (some minor, some major) on 64-bit amd64 are
proprietary junk like flash that doesn't/didn't have 64 bit binaries
available....not relevant at all for a pure open source mail server.

> The smallest WD Raptor drives are 36 GByte which mean, I need at least
> 7 of them but maybe I will go with a 3w9560-8 which can do Raid-6 (for
> the Mailstorage).  The problem will be only the price for the disks
> (800 Euro) and for the controller (800 Euro) since mainboards and CPU's
> plus Memory are going cheap.

for a load of only 40,000 msgs/day, why waste the money on fast but
expensive scsi drives like these?

get a pair of 160GB SATA drives for the mail store, and run them in
software raid-1. they'll give you slightly more space (160GB vs 144GB),
cost a fraction of the price, and they will be significantly faster
because it's only raid-1 rather than hideously slow raid-5.

(raid-1 is many times faster than raid-5 without NV write cache. it's
even a lot faster than raid-5 *with* NV write cache).

and get another pair for the OS and everything else.

> My limit is currently by arround 1500 Euro.

here in .au, you'd be able to get a headless (no screen or kbd)
dual-core amd64 am2 system with 2GB RAM for about $AUD600.

160GB sata drives are about $AUD60 each, x4 = $AUD240.

all up, around $AUD840.  and that would be massive overkill for the job.

current exchange rate is 1 Euro ~= 1.66 AUD.

so that would be about 506 Euro.  only a third of your budget.

you could enjoy the savings or indulge in some frills:

more than enough left over to bring it up to 4GB RAM if you want, and a
couple of spare 160GB drives (and/or or buy 250GB or 320GB or even 500GB
drives instead of 160s).  

maybe even go for one of the new quad-core amd64 CPUs. they're only
about $AUD100 more. spamassassin is not only a memory pig, it's a CPU
hog too....lots and lots of regular expression comparisons.

there's even enough money left over to buy a fully populate Gigabyte
I-RAM card (battery-backed ramdisk up to 4GB in size, with a SATA
interface) which you could mount as /var/spool/postfix

actually, i just re-read your msg above and you run courier instead
of postfix. mount it as whatever directory courier MTA uses for it's
incoming spool and temporary processing area. that's where a large part
of the bottleneck is in mail processing.


craig sanders <cas@taz.net.au>

A Puritan is someone who is deathly afraid that someone, somewhere, is
having fun.

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