Unable to Set Kernel Parameters

[sunil m. r]

Hi,
I have a HP-UX 11 B.11.11 U 9000/785 machine. I need to set the kernel parameters to
certain values as it is needed by DB28.1.
While using SAM to do that, it complains that each variable depends upon some other variable
and it results in a cirular loop. Hence, I am unable to set the variables. I cannot do it from command line as many of the variables are not Dynamic.

Am I following the correct procedure? Is there any other way of doing it? Please advise how to do it. Thanking in advance.

--Sunil

[Steven E. Protter]

You are following the correct procedure.

You need to read the messages carefully and adjust the dependent variables.

It is however possible that what you are trying to do is impossible without changing some of the formulas and dependencies.

If you reach the conclusion that you need to do that, do it very carefully and one formula at a time.

If you are uncertain or new to this, get some help.

If you have a software contract, open a call. If you have a trusted person you know that can help, call him/her.

This is serious stuff, can really mess up your box and if you need to hire someone to teach and help you, do it.

SEP

[Patrick Wallek]

SAM is the easiest way to set the kernel parameters. Yes, there are a lot that depend on values from other parameters, but you just have to work through them. You'll get it eventually.

Here is a good kernel parameter doc:
http://docs.hp.com/hpux/onlinedocs/TKP-90202/TKP-90202.html

[Lowell Lindeman]

Hello Sunil,

In my opinion SAM is the only way to go when changing or tuning the kernel because it does warn you of other dependencies.

Is the console hanging or does it come back after a period of time? As far as clearing up those dependencies, you will have to sort through the list manually to resolve them.

May be of more help if I knew which variables you are trying to tune and what values you would like to set them at.

[William Wong_2]

SAM requires that you make changes to the kernel parameters in a certain order as it is enforcing legal values. However you can instead generate the a new kernel outside of SAM and make the changes in a file which won't have that issue. Be careful if you use this route if you are using the incorrect values that you make a backup copy of your currently working copy of /stand/vmunix so that you can boot up to it in case you didn't not use the correct values and end up with an unbootable kernel. The steps are as follows:

1) cd /stand/build
2) /usr/lbin/sysadm/system_prep -v -s system
3) vi /stand/build/system
4) make all the changes as instructed
5) mk_kernel -s system
6) cp /stand/system /stand/system.working
7) cp /stand/vmunix /stand/vmunix.working
8) mv /stand/dlkm /stand/dlkm.working
9) mv /stand/build/system /stand/system
10) mv /stand/build/vmunix /stand/vmunix
11) kmupdate
12) shutdown -r -y 0

And it should boot. If not boot up to /stand/vmunix.working and repeat the steps
until you get the kernel parameters correct.

[twang]

It seems correct, but you may try it manually:

# cd /stand/build
# /usr/lbin/sysadm/system_prep -s system
(make your kernel changes)
# mk_kernel -s system
# kmupdate
# shutdown -r -y 0

[Martin Johnson]

When I cannot easily use the formulas, my work around is usually to add some value to the formulas, e.x. (formual)+x. This limits the change to just one parmeter (unless the entire vaule of the parmeter is used in another formula).

HTH
Marty

[Caesar_3]

Hello!

You do it ok, just you need to work first
on the depend value.
Like some recursion.

Caesar