topic memory-related checks in Operating System - HP-UX

memory-related checks

Mihai Matei — Mon, 09 Jun 2003 14:14:33 GMT

Hi,
I'm researching memory-related 'rules of thumb' for HP-UX 11.0, 11.11, 11.22. These will be used in a program that should automatically generate warnings about the following:
- free memory pages below lotsfree, desfree, minfree -> memory pressure
- lotsfree, desfree, minfree differ from default -> not recommended by HP
- pageouts/deactivations detected -> free memory is scarce
- oversized/undersized buffer cache -> if bufcache>MAX(300MB, 10% Physical Memory) or bufcache(these values are only orientative, suggestions about the thresholds are welcome)
- Pseudo-swap is disabled.
- Process with a large RSS detected -> if RSS(process) > 20% of main memory (thresholds are again, orientative, suggestions welcome)

What other such rules would you suggest? Relating to memory tunable parameters, kernel size etc.

Thank you.

PS. The thresholds will be configurable, and the 'warnings' are only informative... if you could suggest areas to check for memory issues, it would be great.

Re: memory-related checks

Bill Douglass — Mon, 09 Jun 2003 19:17:39 GMT

You might want to include physical vs. logical reads/writes (effectiveness of your buffer cache).

What type of application(s) does this machine host?

Re: memory-related checks

Mihai Matei — Tue, 10 Jun 2003 07:38:18 GMT

The program could be run on any HP-UX 11.0 - 11.22 system.

Any other ideas?

Re: memory-related checks

Mihai Matei — Tue, 10 Jun 2003 14:45:33 GMT

Bill,
could you give more details about the ratio of physical reads/writes to logical ones? Am I correct in saying that this ratio is given by sar -b, in the rcache and wcache columns? If so, what woud be an acceptable number for those, so as to say the system is performing normally: over 90% for rcache and over 60% for wcache?
Thanks.