Kernel tuning: SAM builds an unbootable kernel image

[Alexander Russell]

Problem:
I am trying to configure a 'boat load' of semaphore undo structures, (inc. per process: semmns, semmnu, semume). When I tune semmnu and semume to near (or at) their maximum configurable values, SAM manages to build the kernel with no warning(s) or error(s), but when I refer to the system console, the system has hung booting the new kernel, (it never gets as far as relocating pdc pages--which I use as an early indicator of kernel image rebuild success on my system).

Questions:
1. Why can't I build a bootable kernel with these parameters set at their maximum values
2. What can I look for in any logs to indicate/preempt an unbootable kernel
3. Can anyone point me to an online guide for compiling the kernel *manually*, i.e. without SAM (but still allowing me to GUI configure the kernel, just not go through with the build/move new kernel steps)

Background:
I have two L-class server (4x440MHz, 4GB memory) machines. MQSeries is complaining of not enough resources trying to do a semop. I am trying to configure my machines to allow more semaphore resources. I will try in the meantime to reduce the number of semaphore resources to see if I break earlier.

Many Thanks for any replies.
Alexander Russell

[Jason VanDerMark]

A good reference for anyone who is going to be doing kernel tuning is the HP-UX Kernel Tuning and Performance Guide. It can be found all over the web. Here is the URL:

http://www.uwsg.iu.edu/hp/hpux-tune.html

I hope that you find it to be useful.

Good Luck,
Jason V.

[Brian Markus]

The guide that he's linking to was co-wrote by Stephen Ciullo. I had the pleasure of attending one of his tuning seminars. He's one of the Top Guru's in HP for this subject. Check that doc, he wrote one other as well. Here's a little known secret: If you have HP support you can actually request your support engineer to have Stephen Ciullo do a proformance analysis on your machines for 4 - 6 units. He does a full write-up with graphs and reccomendations. Let me tell you, this guy knows to much about this subject. He's the only guy i've ever meet that could answer EVERY question about HP-UX I've thrown at him. He knows all the C library functions and procedure calls by heart, and how the kernal interacts with evertyhing.

[Ronald Bolante]

hi Brian Markus... Does Stephen Ciullo have a website or email address where you can ask him more about HP-UX? please tell me so... thanks...

[Bill McNAMARA_1]

look at the mans of the /usr/sbin/km*
commands. SAM is however, typically going to make sure that your system is bootable after recompilation by ensuring values stay within a supported/recommended range. Backup your current kernel to /stand/vmunix.back before you build it manually just so you'll be able to reboot from ISL off the backup kernel should something go wrong.

kmtune for example to tune the kernel
kmupdate and kminstall to install it.
mk_kernel to build it.

Later,
Bill