Poor performance of SunOS 4.0 on 4 MB Suns

[Michael A. Cooper]

There's been some talk in sun-spots on the poor performance of SunOS 4.0
on 4 MB Suns.  We've noticed this also.  Our users are running with the
old SunOS 3.2 Suntools and things are still much slower than they were
under SunOS 3.2 and 3.4 on 3/50's and 3/60's.  On memory "rich" machines
such as a 3/160 with 20 MB and 4/2[68]0's with 32 MB, SunOS 4.0 works
great.

I had heard rumors that this problem was discussed at the Florida SUG and
some suggestions offered.  I'd appreciate hearing about anything from the
SUG or other suggestions.

[[ Are you running the generic kernel on those machines?  If you are, that
should be the first ting to change (don't laugh, people do it).  Sun had a
document at their booth describing ways to improve the performance of 4.0
by reducing the memory it used.  Your local service/sales rep. should be
able to get a copy.  Most of the stuff in there is pretty straightforward
(don't run routed, remove unneeded drivers from config, reduce certain
parameters, etc.), but we have yet to try all of them.  --wnl ]]

In SunOS 4.0.1 for the Sun386, the release notes said significant
performance improvements have been implemented, thus reducing the minimum
amount of memory for SunOS to run on a Sun386 from 8 MB to 4 MB.  We are
about to try that by upgrading our Sun386's to 4.0.1 and trying at least
one with only 4 MB.  Does anyone know if the performance improvements in
the Sun386 release of 4.0.1 are going to be put into the Sun-3 and Sun-4
versions of SunOS?

At this point, we're going to have to downgrade all of the 4 MB Suns
we have upgrade to 4.0 so far (about 30) and postpone upgrading all
other 4 MB Suns on campus until we find a solution.

Michael A. Cooper, University Computing Services, U of Southern California
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