Kernel Changes

[Vito Sarducci]

Here is our problem. We have Java runtime processes (JRE's) on our K580 that eats up CPU and memory. The vendor has directed us to use the HP default Java runtime kernel configuration for our HP-UX server.

We changed the kernel parameters back to the default base kernel parameters and modified these additional ones based off the vendors recommendations;

1. MAXUSERS=400
2. NKTHREAD=6000
3. MAX_THREAD_PROC=3000
4. SEMMNI=1024
5. SEMMNS=16384
6. SEMMNU=2048

Now, this is after we went back to the base HP kernel parameters.

When we rebooted, the server would not come back up? What could have caused this and where can I go look for any clues to the server not coming back up?

Your Expertise is appreciated?

Vito

[Corthouts Carlo]

Are you able to boot into single user mode?

Tried booting from the vmunix.prev?

[Sanjay_6]

Hi,

Boot using the old kernel. At the boot prompt type "bo pri" to boot using the disk on primary path and say "y" to interact with ipl. At the ipl prompt type "hpux -is (;)/stand/vmunix.prev"

This will boot using the old kernel in single user mode. You can then look for the problem. Make a copy of /stand/vmunix.prev in /stand, so that you'll have a copy of good kernel, incase you rebuild the kernel and the current copy gets overwritten.

Hope this helps.

Regds

[Vito Sarducci]

No, we just rebooted from vmnunix.prev at the ISL. We did not try to go into Single User Mode.

What could have caused this? Where can I look?

[Krishna Prasad]

I would first boot of the old kernel to get back. Then I would compare the old system file ( The one used for the vmunix.prev ) to the system file that was used the created the bad vmunix file. I would check and make sure all the drivers needed where in the new system file.

Also, are you running 32bit or 64bit OS on your K580?

[Vito Sarducci]

No, were running 32bit kernel on this server. Were running 11.x in 32bit mode.

[Roger Baptiste]

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Where exactly did it stop or hang?? Does it give any error messages at boot time?

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You can boot from the old kernel. Use SAM and change the kernel params again and regen the kernel. SAM has a more foolproof way of catching errors and incompatible parameter values during kernel regen.

HTH
raj

[Vito Sarducci]

it would not boot the kernel

[Vito Sarducci]

Where else can I look on the system to find out what might have happened? What logs would indicate there might be a kernel problem?

also, the only thing i see in any logs so far is a magic problem during the reboot.

Magic number wrong (namelist mismatch?)

Any guidance is greatly appreciated?

Vito

[Tim D Fulford]

Hi

I took a look at you kernel params, they look fine (imho) except max_thread_proc=3000, the default is 64!

I do vaguley remember from way back that max_thread_proc should not be set too high else programmers can bring the M/c to a halt by issuing too many threads.

just my 0.02??? worth

Tim

[S.K. Chan]

If you're getting the error
Magic number wrong (namelist mismatch)
it means the content of /stand/vmunix does not match that of /dev/kmem (the kernel that is loaded into memory).