just to throw in my 2 cents-
we've built a linux toaster setup here that we call our "cluster". right
now it's 4 boxes sitting behind a layer 4 switch from foundry networks. the
switch does automatic load balancing over the machines (right now it's round
robin, but it can give weightings to different machines), and it will also
remove a machine from the cluster if it stops responding.
anyway, the 4 machines are kind of a mix, but they're all p2-300's or better
with plenty of ram. what we've found from our testing is that the backend
disk storage is almost always going to be the bottleneck and the single
point of failure.
our cluster does SMTP inbound and outbound, storing the messages on a
central spool (currently NFS, gack), and it also does POP access. load
testing proved that qmail could queue up the local disk substantially faster
than things could be delivered to the final endpoint over NFS. still, we
estimated that these 4 machines could probably handle around 3 million SMTP
messages a day (that's from SMTP session start until message is queued),
around 500k deliveries/day, or some combination thereof, but that's
dependent on NFS.
from the SMTP side, the cluster appears to scale almost linearly. on the
local delivery and POP side, we're looking into some high end storage
systems to better manage the load. EMC has a product called Celerra that
looks neat; if anyone has any experience with it i'd love to hear about it.
one thing we've done is to use separate network interface cards for the
"front side" and "back side". that is, all internet traffic goes over one
card, and all the NFS traffic goes over another. this keeps traffic from
going over the same wire more than once (ie, a large message will go over
the internet card once, and over the NFS card once, rather than a single
card twice). anecdotal and empirical evidence seems to suggest it's faster,
but YMMV.
shag
=====
Judd Bourgeois | CNM Network +1 (805) 520-7170
Software Architect | 1900 Los Angeles Avenue, 2nd Floor
[EMAIL PROTECTED] | Simi Valley, CA 93065
...yours is not the less noble because no drum beats before you when
you go out into your daily battlefields, and no crowds shout about your
coming when you return from your daily victory or defeat.
--Robert Louis Stevenson
----- Original Message -----
From: David Dyer-Bennet <[EMAIL PROTECTED]>
To: Qmail <[EMAIL PROTECTED]>
Sent: Fri 6 Aug 1999 14.14
Subject: RE: Performance
> Tim Hunter <[EMAIL PROTECTED]> writes on 6 August 1999 at 16:36:48 -0400
> > Makes me amazed at the machines that people have to run mail anymore.
> > My company mail server is a p75, 32M, 2G IDE
> > I have only 30 users but alot of throughput, never had any problems
with
> > queuing or ever had to reboot for any reason other than a kernel
update.
> > Maybe I should run some benchmarks just to show how great qmail is on a
> > piece of dirt machine.
>
> I'd be interested in seeing that sort of statistics too -- closer to
> my real world, for one thing :-) .
>
> Note that the person whose configuration you were marveling at is
> looking to move 10 MILLION customized individual email messages a day.
> His configuration is much bigger than I use for moving mail -- but
> he's aiming at moving several orders of magnitude more mail than I
> move, too, so that seems fair.
>
> (And gee it's smart to build a test configuration and do some
> benchmarking before committing to something that seems likely to push
> the limits of hardware / software technology!)
> --
> David Dyer-Bennet ***NOTE ADDRESS CHANGES***
[EMAIL PROTECTED]
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