How to take a backup of HP-UX Kernel before patching or modifying the kernel parameters

There are situations wherein at the time of applying the patches, or making tunable changes the kernel parameters we need to have a roll back plan to revert to the older kernel in case things go wrong.

The backup of a the existing running kernel helps in there. Depending on the fact that the system is a pre 11.23 (like 11.00 11.11) or post 11.23 inclusive of 11.23 like 11.23 and 11.31 here is how you can take a backup copy of the existing kernel.

For 11.11, 11.00 etc.
------------------------

cd /stand/build

/usr/lbin/sysadm/system_prep -s system

The above reads the current system and prepares a system file in /stand/build

Once the system file is created , create a kernel out of that  (the new system file and kernel will be placed in /stand/build to avoid the confusions)

/usr/sbin/mk_kernel -s system

This creates the kernel vmunix_test

For 11.23 as well as 11.31
===================

kconfig -e /stand/system.test

This exports the configuration of the current running kernel.

Import the same, to be noted that the import creates the a new kernel with the configuration which you have exported. That is the kernel as per the current runaning configuration which you can use to boot from in case you need to roll back.

Importing the exported config

kconfig -i hpux_test /stand/system.test