kernel tuning with kcweb questions...

[inventsekar_1]

hi,
i have lot of question in kernel tuning.

1.) i like the kernel tuning with sam(sam TUI) in HP-UX 11i. but with 11iv2, i feel difficult to tune the kernel with IE. then i think why they changed sam method of tunning the kernel? what is good in web interface kernel tuning?

2.) i read that "ncallout" is the kernel parameter which admins need to change often and also it requires reboot. is ncallout available with 11iv2? i am not seeing it with "kctune" command?

[Steven E. Protter]

Shalom,

They've been talking about a web based kernel tuning system for years. There have been several surveys from the sam team on these very forums on the topic.

Most experienced sysadmins reject this out of several reasons. We like to know how to do things on the command line because sometimes thats all we have to work with.

I took a look at sam on an 11i v2 system a few weeks ago. It doesn't look all that different from the 11i v1 tuning.

11i v2 has replaced kmtume with kctune. A lot of kernel parameters can be tuned on the commmand line without booting your system.

I recommend looking at the man page for kctune and trying it out. You will find shortly you need no gui for this kind of work.

As to the ncallout kernel parameter, it appears to be gone on my Itanium 11i v2 system. Looks like it was taken away for some reason. Perhaps a peak at the OS release notes will help explain it.

SEP

[Mridul Shrivastava]

Try running kmtune -q
It will show you either it is dynamic or not. If its dynamic then it doesn't require a reboot else it requires a reboot.
I have one 11.11 system and I checked there and found that it's value is (16+NKTHREAD).
So we need to chenge that parameter value and check for it.

[Michael Steele_2]

The biggest obsticle in using a GUI like IE with any computer, not just a enterprise server, is disaster recovery. GUI drivers don't enable until run-level three.

Think of a wireless keyboard or wireless mouse. You can't use it to interface with the BIOS or WINDOWS SAFE mode. The same is true for UNIX Enterprise servers. GUI's don't enable in single user or run level 2.

1) See above. A bad kernel renders a non-bootable system. In this case you'd have to locate a TUI at the console.

2) NCALLOUT (NKTHREAD+16) in 11.23.

kmtune -q NCALLOUT -S /stand/system

[Don Morris_1]

Yup, looks like ncallout was obsoleted between 11i v1 and v2. The kernel handles it internally now, with a backup tunable named "callouts_extra" in case that heuristic fails on your workload.

man callouts_extra for gory details. (man 5 if you need to supply the chapter for some reason).