SUMMARY: 4/690 takes naps!

From: Mike Daffey (
Date: Thu Feb 17 1994 - 02:50:10 CST

(Abridged) original posting:

>Some tuning advice needed. I have a customer with a 4.1.2 4/690 which
>under moderate load decides to go to sleep for a few seconds every so often.
>ie as far as we can tell NO-ONE gets to do anything during this time.
>Long directory searches (ls -l on 2000 files) seem to be the problem.
>System has 130 odd users, 128Mb memory.
>Reducing MAXUSERS from 120 to 90 helped, reducing the pauses from a maximum
>of 5-6 seconds to 2-3.

It looks as though things are OK now. Glenn Satchell wrote saying he'd seen
the same phenomenon and that reducing MAXUSERS was the way to go. He also
suggested that 4.1.3 (as did Robert Wolf) would be the ideal solution.
We were running a little tight in a couple of areas, so as a first attempt
left MAXUSERS at 90 and changed param.c to drop nfile by about 1500
and ncsize from ~1600 to 1000. Before this change the site had found
that a few simultaneous WordPerfect <LIST-FILES> alone were enough to
generate these pauses. After rebooting with the new kernel it was
impossible to reproduce the problem. DNLC hit rates are still reasonable (~90%).

There are plenty of warnings that setting MAXUSERS high on large 4.1.2
systems can result in a kernel panic on boot, but I couldn't find anything
in SunSolve which did more than hint that there might be performance problems
introduced as one approached this point. Those who are stuck on 4.1.2 with
large servers be warned, particularly if you are contemplating a memory upgrade.

Many thanks to:

Pat Cain <> (Hal Stern - NE Area Systems Engineer) (Glenn Satchell - Uniq Professional Services) (Robert Wolf)
Mike Daffey,
Fujitsu Australia phone +61 3 8685583
20 Queens Road fax +61 3 8685741
Melbourne VIC 3004 Australia

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