[ILUG] Linux SMP on Xeons

[Paul Trainor]

AMI Megaraid should do the job.

-----Original Message-----
From:	ilug-admin at linux.ie [mailto:ilug-admin at linux.ie] On Behalf Of Colm
Buckley
Sent:	15 June 2000 09:28
To:	ilug at linux.ie
Subject:	Re: [ILUG] Linux SMP on Xeons


Various people write:

>>> Just wondering whether anyone has real experience of running Linux on a
>>> 4- or 8- way Xeon system.  Any gotchas?  Does performance scale well
>>> with CPUs?  The system in question is likely to be a high-performance
>>> mail relay, running a carefully-tuned exim...  I'm hoping that, given
>>> enough CPU and RAM (say 4 Xeons and 4GB), I'll be able to handle
>>> something like 80,000 emails per hour.

>>  Mail is I/O bound.
>>  From a "# of cpus" point of view, probably over-spec.

> Way, way over.

Noted.  I might leave it as it is, though, to leave room for the system
to grow.

>> Make sure you have a separate, fast disk (goat type)

> Goat type? Eh, what? I'm assuming that's a weird way of saying 10,000
> RPM disk 8)

Yep, that's a given.  I'm looking at 2 9GB 10k LVD drives, with some
sort of RAID arrangement, ideally with a hardware RAID controller with
NVRAM write cache, for the queue dir.  (Does anyone know of such a beast
with Linux support?) ReiserFS seems like a good bet for this directory, too.

> For the mail directories, (assuming they're on this machine in an
> exported /var/mail or an IMAP server message store), I'd do mirrored
> stripes if I had the disks, grudgingly settling for RAID5 if not.

Not really an issue - almost all the mail in question is outgoing (the
application is 'managed mailshots to a customer db').

Linux on Intel is pretty much a given - performance/price is higher than
for most other server platforms, and there are management and
homogeneity issues - I'm sticking with what I already have and know.

As for MTA, it's pretty much a straight fight between exim and postfix.
Q- er, "the scottish MTA" is ruled out basically beacuse of the attitude
of its author, which I don't find encouraging.  Exim I like and know,
but postfix is apparently faster in raw terms - however, I know that
Demon and Freeserve are both using exim on fairly modest machines to
handle mail, so I figure it should be able to cope.  If it can't, I'll
switch to postfix - this is quite easy, as local configuration is
minimal on the machine in question (one local domain, no address
rewriting, only a few standard aliases, simple trust arrangements).

Thanks for all the input, folks.  If someone can think of a suitable
RAID controller, I'll be as happy as the proverbial.

      Colm

--
Colm Buckley BA BF | NewWorld Commerce, 44 Westland Row, Dublin 2, Ireland
colm at tuatha.org (personal) | colm.buckley at nwcgroup.com (business)
+353 87 2469146 | whois cb3765 | http://www.tuatha.org/~colm/
Some days you're the dog, and some days you're the lamppost.

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