tuning the kernel

[Donna Powell]

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.

[Sridhar Bhaskarla · Accepted solution]

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

[Kurtkarl]

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

[Duncan Edmonstone]

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

[BFA6]

I generally use SAM for configuring parameters

Hilary

[S.K. Chan]

# 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

[Sanjay_6]

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

[Roger Baptiste]

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

[Deshpande Prashant]

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

Thanks.
Prashant.

[Mary Ann Lipa]

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