[Beowulf] What services do you run on your cluster nodes?

Greg Lindahl lindahl at pbm.com
Mon Sep 22 15:25:05 PDT 2008

On Mon, Sep 22, 2008 at 03:04:33PM -0400, Perry E. Metzger wrote:

> If a machine isn't sending out more than, say, 20,000 email
> messages an hour, you won't notice the additional load Postfix puts on
> a modern machine with any reasonable measurement tool.

Ah. So if I have 3,000 nodes, running an extremely tightly coupled
app, and each one does postfix once per 30 seconds (that's
100/second), and each time one wakes up it causes the entire cluster
to freeze for 1 quantum (1/250 of a second), how much work does the
cluster get done?

That's the point of one of the papers on this topic; with a high
speed, low latency interconnect, you'd be amazed at the effects that
you can see.

-- greg

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