topic Re: nclist kernel parameter in Operating System - HP-UX

nclist kernel parameter

Nantambu Starks_1 — Mon, 14 Mar 2005 08:59:10 GMT

I am getting "WARNING: cblock exhaustion has occurred" errors within my syslog. My current formula for my nclist kernel parameter is set to (20000+64*maxusers) which gives me an nclist set to 24096. I have 640 MB of physical memory in a D280 machine. I am having to reboot this machine about every 3 days to clean this issue. What is the farthest I can push the nclist parameter out to without adversely affecting the system?

Re: nclist kernel parameter

Steven E. Protter — Mon, 14 Mar 2005 09:13:36 GMT

The usual answer is it depends. One thing it depends on is what maxusers is.

Is this the only parameter you changed last time you did a kernel?

I'm wondering what reason you had to change the formula and add the 20,000.

I'd suggest a non-formula, just a number that meets whatever requirements you have for this parameter.

SEP

Re: nclist kernel parameter

Kent Ostby — Mon, 14 Mar 2005 09:15:58 GMT

Well, there is no maximum per se.

Each increase takes some amount of memory.

There have been some cases of third party applications with code errors that eat up cblocks (if they lock incorrectly).

If you are having this problem on a multi-CPU system, make sure that you check all your applications and make sure that version is suppossed to be able to run on a multi-CPU system.

If you list your apps here, I will try to see if there are any known problems with any of them.

Finally, HP's Support Center might be able to read a dump (you would need to force this with a TOC of your system which would take your system down hard (but give the data for this problem)) and see how the cblocks are being used.

Re: nclist kernel parameter

Pete Randall — Mon, 14 Mar 2005 09:18:34 GMT

Each additional cblock consumes 32 bytes of memory so that's going to be your limiting factor. I would try increasing it until you either experience memory pressure or you stop getting the WARNING, whichever comes first.

Pete

Re: nclist kernel parameter

Nantambu Starks_1 — Mon, 14 Mar 2005 10:20:44 GMT

Thanks for the information.