topic Re: changed kernel parameter not effective after reboot in Operating System - HP-UX

changed kernel parameter not effective after reboot

Thayanidhi — Wed, 30 Apr 2003 11:27:15 GMT

Hi,

I was getting error "fork failed, proc table full"
I found maxuprc low (75), and increased to 200.
Since it is dynamic parameter, it changed. But
After I reboot old value is coming back.
How to make this value permanent?

Thanks in advance.

T.Thayanidhi

Re: changed kernel parameter not effective after reboot

Jean-Louis Phelix — Wed, 30 Apr 2003 11:47:02 GMT

Hi,

Your problem is not related directly to maxuprc, but rather to nproc which is static. If you use kmtune -s for maxuprc, change should become permanent but also check if your nproc value really depends on maxuprc.

Regards.

Re: changed kernel parameter not effective after reboot

Stuart Abramson_2 — Wed, 30 Apr 2003 11:47:07 GMT

1. How did you change the maxuprc from 75->200? I have never worked with "dynamic kernel parameters".

2. Here is how I do it on hp-ux 11.0:

a. SAM:

set display
sam
kernel parameters
change parameter
click okay until reboot now.

b. commands:

cd /stand/build
/usr/lbin/sysadm/system_prep -s system
vi system
# make changes
# maxuprc 200
mk_kernel -s system # makes /stand/build/vmunix_test
ll vmunix_test
cd /stand
cp system system.prev
cp vmunix vmunix.prev
mv dlkm dlkm.vmunix.prev
cp ./build/system system
kmupdate
cd /
shutdown -r 0

Re: changed kernel parameter not effective after reboot

Stuart Abramson_2 — Wed, 30 Apr 2003 11:51:08 GMT

I think the previous answer was right.

"proc table full" comes from nproc too small. You should change nproc.

Re: changed kernel parameter not effective after reboot

Thayanidhi — Wed, 30 Apr 2003 12:02:10 GMT

Hi,

NPROC is static is it enough I feel (4096).
At any movement I don't see processes more
than 300. (ps -ef | wc -l), ans also root
user never gave this erro.

MAXUPRC is change through sam. After reboot
I see in /stand/system "maxuprc 200".
Still I am wondering where from it is picking
up the old value.

Since the maxuprc is dynamic I don't need to
rebuild the kernel correct?

Thanks and Regards

TT

Re: changed kernel parameter not effective after reboot

Ravi_8 — Wed, 30 Apr 2003 12:31:09 GMT

Hi,

did u rebuild the kernel after changing the value.

(ofcourse sam does this while exiting)

you might have choosen to build the kernel later.

choose defaults from in the SAM screen

Re: changed kernel parameter not effective after reboot

Michael Steele_2 — Wed, 30 Apr 2003 12:33:39 GMT

As suggested the 'proc table full' message indicated 'nproc' is too small. View its usage with 'sar -v':

sar -v 5 5

nproc will be listed in numerator / denominator format and designated as "proc-sz". The denominator is your ceiling, the numerator is the current usage. Refer to 'proc-sz' below:

08:06:08 text-sz ov proc-sz inod-sz ov file-sz ov
08:06:10 N/A 0 656/1072 0 900/900 656/656

Use 'kmtune' to display or change its value.

kmtune -q nproc
-or-
kmtune -q nproc -l (* long listing *)

To change 'nproc':
cd /stand/build
kmtune -s nproc=##### -S /stand/build/system
kmupdate /
kmtune -q nproc -S /stand/build/system
mk_kernel -s /stand/build/system
kmupdate /stand/build/system_test
cd /
shutdown -r now

Re: changed kernel parameter not effective after reboot

Bill Hassell — Wed, 30 Apr 2003 12:39:35 GMT

To determine if maxuprc or nproc is causing the error, use sar -v as mentioned before. If NPROC is 4096 and if sar -v shows plenty of empty slots (like 2000 used out of 4096), then maxuprc is the problem. HOWEVER: maxuprc refers to *ALL* processes started by the same user. If 500 people all try to login and start 2 process, then MAXUPRC=200 will stop allowing new processes after only 100 users login.

To see how many processes are being run by a specific user ID:

ps -f -u oracle

which shows all processes owned by the user oracle.

Re: changed kernel parameter not effective after reboot

Thayanidhi — Wed, 30 Apr 2003 12:58:21 GMT

Hi,

I think you misunderstood the question.

If I change maxuprc,I could see the new value after I exit sam using "# sysdef | grep maxuprc". After that system behaves properly.

If I reboot the value changed from 200 to 75,
And giving problems.

When I exit from sam after modifying maxuprc,
sam doesn't rebuild kernel (i.e. Dynamic parameter)

My question is If I modify a dynamic value, do
I have rebuild the kernel forcebly. If so
then why it is called dynamic?

Thanks and Regards

TT

Re: changed kernel parameter not effective after reboot

S.K. Chan — Wed, 30 Apr 2003 13:16:25 GMT

Maybe this is another case of SAM misbehaving ... before we get to that .. I would recommend doing this in command line ..
# kmtune -q maxuprc
==> This shows what's the current value (look at "current" and "planned") they should match. Now say you want to to make it 200, you would ..
# kmtune -s maxuprc+125
# kmtune -q maxuprc
==> You will see planned=200 and current=75.
# kmtune -u
==> Update the change.
# kmtune -q maxuprc
==> Now current=planned.
Check /stand/system to make sure this gets added.
# grep maxuprc /stand/system
The next time you reboot this setting will stay. Now in SAM, after you have changed it, check 2 things..
a) kmtune -q
b) the /stand/system
Are they updated ??

Re: changed kernel parameter not effective after reboot

Patrick Wallek — Wed, 30 Apr 2003 13:22:26 GMT

Have a look at Technical Knowledge Base document UKRNKBRC00010259 located here: http://www2.itrc.hp.com/service/cki/docDisplay.do?docLocale=en_US&docId=200000062922035

I think it will help with your problem.

Also have a look at Technical Knowledge Base document KBRC00001138 located here: http://www2.itrc.hp.com/service/cki/docDisplay.do?docLocale=en_US&docId=200000065680020

I think it may give you some other good background.