[Mailman-Developers] Re: To VERP or not to VERP?

J C Lawrence claw@kanga.nu
Sun, 17 Jun 2001 13:23:48 -0700

On Sun, 17 Jun 2001 09:53:28 -0700 
Chuq Von Rospach <chuqui@plaidworks.com> wrote:

> On Sunday, June 17, 2001, at 09:39 AM, J C Lawrence wrote:

>> Exim for instance will defer deliveries if more than N messages
>> are received in a single connection.  As a result, you typically
>> get no outbound deliveries going on during a qrunner broadcast.

> IMHO, I consider that seriously broken.

Its configurable.

>> I've done similar experiments with news spools.  The values are
>> incredibly subjective to RAID stripe size.  Bob Mende IIRC did
>> some interesting work here which I think he presented at LISA.
>> FWIW We ended up with a 1Meg strip size as the sweet spot, much
>> bigger than we'd expected.

> I know someone who did the same, and found the best perforamnce
> iwth (I kid you not) 32 meg strip sizes.

Not surprised.  Among other things its going to be sensitive to
number of spindles, RAID type, and feed characteristics.

>> Silicon disks are another one.  At Critical Path we used solid
>> state disks for /var/spool and Qmail fairly, umm, whirred.

> But what I've found, for really large e-mail installations,
> there's always another bottleneck. The bigger/faster machine
> paradigm just doesn't scale after a while, so what I'm working on
> now is a new setup that I'm calling the "army of smurfs"
> design. I'm going to be buying lots of small/fast/cheap boxes, and
> not going to try to try to keep making that single monolithic
> machine do incrementally more.

I've noticed that E-Machines are getting popular for precisely that

J C Lawrence                                       claw@kanga.nu
---------(*)                          http://www.kanga.nu/~claw/
The pressure to survive and rhetoric may make strange bedfellows