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

default kernel parameter

malay boy — Mon, 23 Feb 2004 02:54:23 GMT

Hi,
I have made some changes on the kerel parameter according to Oracle recommadation.The result of that the server run very slow.The old kernel parameter either value nor formula I forgot to jot down.So now I just thinking to try to revert to old value and see the performance.If anybody can told me where to find the default value for all parameter it would be great.I attached here my nickel.

regards
mB

Re: default kernel parameter

malay boy — Mon, 23 Feb 2004 02:56:27 GMT

Hi here are the nickel.

regards
mB

Re: default kernel parameter

Hoefnix — Mon, 23 Feb 2004 03:06:08 GMT

You can boot your old kernel vmunix.prev, if it's still in /stand.
Then you will have your old settings back.

See also:
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=31889

HTH,
Peter Geluk

Re: default kernel parameter

Karthik S S — Mon, 23 Feb 2004 03:14:32 GMT

To review your old kernel parameters do a,

cat /stand/system.prev

-Karthik S S

Re: default kernel parameter

Hoefnix — Mon, 23 Feb 2004 03:22:20 GMT

The problem with the /stand/system.prev that it only contains the changed tunables and not the defaults.

What you can do is delete the kernel tunable that you like to get back to default from /stand/system and then use this system file to build a new kernel. Then the kernel will be build with the default for this tunable.

HTH,
Peter

Re: default kernel parameter

Hoefnix — Mon, 23 Feb 2004 03:26:05 GMT

I looked at the manpage of kmtune:

kmtune -r will reset it to the default value.

-r name
Reset the value of a system parameter to the default.

HTH,
Peter Geluk

Re: default kernel parameter

Fabio Ettore — Mon, 23 Feb 2004 04:38:18 GMT

Hi mB,

if you have a HP-UX 11.X system then launch

# kmtune -l

This command reports all kernel parameters with actual and planned value (that is before and after kernel rebuilding), and default values too.

And you can report it to default value but Peter's suggestion is very good too. -r option will report a kernel parameter to default value. (Very good Peter, I didn't see it before, of course I never reported a kernel parameter to default value) :-)

Best regards,
Ettore

Re: default kernel parameter

Hoefnix — Mon, 23 Feb 2004 06:36:19 GMT

Ettore,

I like the kmtune -l you suggested, but it's a pitty that it's showing formula's for the default with already filled in values and not the variable(kernel-tunable) that it's using to calculate :(

But still its a nice feature to do some kernel investigation.

Regards,
Peter

Re: default kernel parameter

Geoff Wild — Mon, 23 Feb 2004 08:45:12 GMT

Though you have to read through the doc, it does tell you what the default is for each (most?) kernel parameters:

HP-UX 11i

http://docs.hp.com/hpux/onlinedocs/TKP-90202/TKP-90202.html

HP-UX 11.0

http://docs.hp.com/hpux/onlinedocs/939/KCParms/KCparams.OverviewAll.html

Rgds...Geoff

Re: default kernel parameter

malay boy — Mon, 23 Feb 2004 21:13:35 GMT

Thanks everybody.

Quick question - 512mb memory for running 3 oracle database size 8G with 100 users doing programming / testing , is 512 enough?.

regards
mB

Re: default kernel parameter

Patrick Wallek — Mon, 23 Feb 2004 21:46:47 GMT

How big is your SGA? My first reaction is no, it's not enough. I would be more comfortable with at least 2GB.

Re: default kernel parameter

Con O'Kelly — Mon, 23 Feb 2004 21:50:22 GMT

Hi mB

512MB for 3 Oracle Databases is nowhere near enough. For Oracle I'd be looking for at least 2-3GB.

Cheers
Con

Re: default kernel parameter

Michael Tully — Mon, 23 Feb 2004 22:22:57 GMT

Depending on the size of the SGA, I would suggest 4Gb as a minimum. This may depend on the size of the tables being used. Are we talking about 8Gb each or in total ...?

Re: default kernel parameter

T G Manikandan — Mon, 23 Feb 2004 22:31:48 GMT

100 users 3 databases,512 MB.Definitely no.
Probably you can keep them running but the performance would be very bad.

The queries would be very slow.