Reconfiguring an HP-UX (11iv1) kernel

It's whole new experience [heaven]. I thought it will remain a wish. Performing this is a long-shot in our working environment. But, what could be sweeter than a wish coming true? Nada! Of course, other than.. nah, nevermind! Ok, we have a project to have a kernel parameter changed. Upon doing a prework, we have this initial value:

[root@hpux09:/stand/build]
# kmtune -q vx_maxlink
Parameter Current Dyn Planned Module Version
==========================================
vx_maxlink 32767 - 32767

[root@hpux05:/stand/build]

We usually perform these kind of changes via SAM. But, wait! What the f*%$? Where's the vx_maxlink parameter?!? "Uhmm, hey [referring to my colleague], can you check it with L3?" So that's it. There are some parameters that does not show [or linked] on SAM. Changes to be made are to be performed via CLI. So, here are the steps I followed:

[root@hpux09:/stand/build]
# /usr/lbin/sysadm/system_prep -s system

[root@hpux09:/stand/build]
# kmtune -q vx_maxlink
Parameter Current Dyn Planned Module Version
==========================================
vx_maxlink 32767 - 32767

[root@hpux09:/stand/build]
# kmtune -s vx_maxlink=65534

[root@hpux09:/stand/build]
# kmtune -q vx_maxlink
Parameter Current Dyn Planned Module Version
==========================================
vx_maxlink 32767 - 65534

[root@hpux09:/stand/build]
# which mk_kernel
/usr/sbin/mk_kernel

[root@hpux09:/stand/build]
# mk_kernel -s system
Generating module: krm...
Generating module: SEOS...
Compiling conf.c...
Loading the kernel...
Generating kernel symbol table...

[root@hpux09:/stand/build]
# kmupdate

Kernel update request is scheduled.

Default kernel /stand/vmunix will be updated by
newly built kernel /stand/build/vmunix_test
at next system shutdown or startup time.


[root@hpux09:/stand/build]
# shutdown -ry 0
Shutdown cannot be run from a mounted file system -- exiting shutdown.
Change directories to the root volume ("/" will work) and try again.

[root@hpux09:/stand/build]
# cd /

[root@hpux09:/]
# shutdown -ry 0

SHUTDOWN PROGRAM
05/24/08 23:40:31 EDT

Broadcast Message from root (pts/5) Sat May 24 23:40:31...
PLEASE LOG OFF NOW ! ! !
System maintenance about to begin.
All processes will be terminated in 0 seconds.

Broadcast Message from root (pts/5) Sat May 24 23:40:31...
SYSTEM BEING BROUGHT DOWN NOW ! ! !

/sbin/auto_parms: DHCP access is disabled (see /etc/auto_parms.log)

For now, we have to wait for box to come up and check if the change we applied took effect. [Cross-finger] Hoping it did.?! It's driving me crazy [and very excited!].

What the f*%$ have I done?? I am doomed! The kernel parameter didn't change at all. The value is still under planned. My heart raced and pounded. Hey! I'm no superman. Looking for a reason to have the window time extended. Deym! [Temporary, still to hear a LOT about this during our weekly meeting] Fortunate for me (?), the change was so important that it left no choice for the application team, requestor, and box owner to extend the time and allow me to give it another go. But, this time? I got L3's attention! I consulted them, and they gave me an SOP [btw, for the record, of which I'm not aware of and was not provided]. [Another] But, to make sure, I let the L3 do it [I got my hands tied already, so I'm not taking any chances - not now but, definitely will love to do it again, anytime, anywhere!], and check how he did it a bit later. A few, very long, minutes later, he's working his magic. And here's how:

cd /stand/build
ll system [optional but essential]
kmtune -q vx_maxlink
/usr/lbin/sysadm/system_prep -s system
kmtune -s vx_maxlink=65534 -S ./system # This is what I missed; writing to system file
/usr/sbin/mk_kernel -s system
kmupdate
cd ..
cp -p system system_prev
mv build/system .
kmtune -q vx_maxlink
[now all I need is to reboot the box, and done!]

Well, folks, I hope you learned new. For me? I learned a TON!

And oh, make sure to watch out for the /stand FS getting full. You might end up just like it. I tell you, it's nasty. May be giving a system_prep will clear it... Well, just a thought. Good luck to us all.


This was added a bit later [July something of 2008].

Here's the procedure for HPUX 11.23: (explanation? Later)

# mv /stand/system /stand/system.orig

# kconfig -e /stand/system

CEdit /stand/system file and remove all "Tunable Parameters".
Copy and paste Tunable parameters ( lined between START KERNEL PARM and END KERNEL PARM) from /tmp/logfile.
Save and exit.

# kconfig -i /stand/system

# shutdown -r 0