SUMMARY: Virtual Memory

From: <simon.millard_at_barclays.co.uk>
Date: Mon, 19 Jul 1999 08:45:13 +0100

Dear Managers,

Sorry about the delay in posting this summary.

Thanks to the following who provided me with some insight into virtual
memory.

N.M.Hill_at_rl.ac.uk
juredd_at_axcion.com
Caprica7_at_aol.com

Firstly, the amount of virtual memory has nothing to do with physical
memory. I do remember from my DU training courses that there is not
enough memory in the world that DU can address.

The nub of the replies was that you can increase the amount of virtual
memory that a user can use by adjusting the following.

vm:
 vm-maxvas

proc:
 per-proc-data-size
 max-per-proc-data-size
 max-per-proc-address-space
 per-proc-address-space

These parameters were increase to 2147483648 each, apart from
per-proc-data-size which was set to 262144000. The system was rebooted
and each users vmemory value (from ulimit -a) indicated an increase
from 1Gb (the default) to 2Gb.

One gotcha is that ulimit displays different things depending which
shell you use, the 3rd party support company was using csh which
increased values considerably.

It got to the stage where the 3rd party came onto site to perform a
health check of the application and OS. It turned out that ingres
required tuning and the number of threads it used increased.

Nice to know that ingres can have a bad day too.

Simon


Simon.Millard_at_barclays.co.uk
Group Mail: Simon S.G. Millard

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Received on Mon Jul 19 1999 - 07:54:57 NZST

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