becker at scyld.com
Fri Oct 5 01:47:29 EDT 2001
On Thu, 4 Oct 2001, Tim Carlson wrote:
> On Thu, 4 Oct 2001, Donald Becker wrote:
> > > If you were running
> > > 1000 small jobs in a couple of minutes I could imagine having problems
> > > authenticating against any non-local mechanism.
> > Hmmm, a reasonable goal is running a small cluster-wide job every
> > second. I suspect the NIS delays alone take longer than one second with
> > just a few nodes.
> So I ran the following test on one of our small clusters.
> 6 client NIS nodes with one NIS master (front end node) and no NIS slave
> servers. Dual 800Mhz Pentium IIIs connected on a fast ethernet switch.
I wouldn't expect request drops or significant delays with just 6
clients. The interesting activity starts around 30 nodes.
Still, having hard numbers for even 6 nodes is a good baseline.
> Now I point this script at 6 nodes at the same time (or at least as fast
> as I can type a return in 6 xterms) and the mean time per run is about 31
> seconds. That puts my potential NIS delay at a maximum of 1/3 of a
> second. But I have also launched 600 jobs in 31 seconds.
> Before and after "ps -ax | grep ypserv" on the master node.
> 639 ? S 73:08 ypserv
> 639 ? S 73:10 ypserv
> So I used 2 seconds of CPU time with ypserv
Donald Becker becker at scyld.com
Scyld Computing Corporation http://www.scyld.com
410 Severn Ave. Suite 210 Second Generation Beowulf Clusters
Annapolis MD 21403 410-990-9993
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