topic Re: tuning the kernel in Operating System - HP-UX

tuning the kernel

Donna Powell — Mon, 26 Nov 2001 16:22:46 GMT

I am in the process of setting up a new system. I need to tune my kernel parameters. Here are the
steps that I have. Can someone just confirm that these steps are correct or not. If not, please direct me to the proper help doc, or give me the proper commands:

kmtune -s | more to get a print out of all the tuneable parameters set on my box.

kmtune -s (parameter name=value) to change the value on a parameter.

cp the system file in /stand to a new filename to a temporary spot

cp the vmunix file in /stand to another filename to a temporary spot.

mk_kernel -s ./system this will rebuild my new kernel using the system file and create vmunix_test once this file is created, I can then move in the vmunix_test into /stand and reboot the system for the new kernel to take effect.

Re: tuning the kernel

Sridhar Bhaskarla — Mon, 26 Nov 2001 16:26:50 GMT

Donna,

You are correct. You don't need to specify -s with the mk_kernel as it is default.

You can do the following way.

Copy /stand/system as /stand/system.date
Copy /stand/vmunix.prev as /stand/vmunix.old if you want to preserve two levels of kernel.
Your current kernel will be automatically moved as vmunix.prev with the following mk_kernel command.

#kmtune -s (param name=value)
#mk_kernel -o /stand/vmunix
#shutdown -r now (Don't use reboot here)

-Sri

Re: tuning the kernel

Kurtkarl — Mon, 26 Nov 2001 16:27:10 GMT

Hi,

This is how I usually do it when I'm making changes on our kernel.

* To change/configure kernel.
- cd /stand/build
- /usr/lbin/sysadm/system_prep ???s system
- vi system
Build new kernel
- /usr/sbin/mk_kernel ???s ./system
note: this will create /stand/build/vmunix_test file. Always backup orig system and vmunix files first
- mv /stand/system /stand/system.prev
- mv /stand/vmunix /stand/vmunix.prev
- mv /stand/build/system /stand/system
- mv /stand/build/vmunix_test /stand/vmunix
- reboot the machine
Thanks
Joey

Re: tuning the kernel

Duncan Edmonstone — Mon, 26 Nov 2001 16:30:36 GMT

As many kernal parameters are inter-dependent, this is one are where I like to let SAM do the leg-work, it's also one of the better functional areas within SAM! - Doing it by hand I've seen people end up with a non-bootable kernal... I've never seen sam screw this up.

HTH

Duncan

Re: tuning the kernel

BFA6 — Mon, 26 Nov 2001 16:32:49 GMT

I generally use SAM for configuring parameters

Hilary

Re: tuning the kernel

S.K. Chan — Mon, 26 Nov 2001 16:34:25 GMT

# cd /stand/build
# /usr/lbin/sysadm/system_prep -v -s system

kmtune -S /stand/build/system -s parm_name=value
or
kmtune -S /stand/build/system -s parm_name+value

kmsystem -S system -c y driver_name # these utilities modify the system file at 11.0

# /usr/sbin/mk_kernel -s ./system

# mv /stand/system /stand/system.prev #new for dynamically linked modules at 11.0

# mv /stand/build/system /stand/system
# kmupdate # kmupdate automates moving the kernel files into the proper directory

# shutdown -ry 0

Re: tuning the kernel

Sanjay_6 — Mon, 26 Nov 2001 17:42:00 GMT

Hi Donna,

Here is a thread on kernel rebuild from hp doc site,

http://docs.hp.com/cgi-bin/fsearch/framedisplay?top=/hpux/onlinedocs/B2355-90742/B2355-90742_top.html&con=/hpux/onlinedocs/B2355-90742/00/00/32-con.html&toc=/hpux/onlinedocs/B2355-90742/00/00/32-toc.html&searchterms=kernel%20build&queryid=20011126-094517

Hope this helps.

Regds

Re: tuning the kernel

Roger Baptiste — Mon, 26 Nov 2001 17:47:03 GMT

Donna,

Remember to run kmupdate before doing the shutdown!! This is important otherwise the dlkm files wont get moved and you will have a system which gives weird problems later on.

-raj

Re: tuning the kernel

Deshpande Prashant — Mon, 26 Nov 2001 23:00:06 GMT

HI
You will need to run kmupdate before rebooting machines, after kernel is built manually using mk_kernel with -o option.

Thanks.
Prashant.

Re: tuning the kernel

Mary Ann Lipa — Tue, 27 Nov 2001 00:39:20 GMT

Hi Donna,
I usually usa sam , and let it do the job. never experienced any kernel screw up, ever. Also kernel parameters are often interdependent you have to change this to change that, (sam knows that). Anyways... you're on the right track compiling a new kernel via command line

d_b