HP-UX Tips & Tricks Site

Hi,

I didn't know about the posibility of booting in Fail-Safe mode. If you have made a mess of the last kernel parameters/modules configuration and don't have a backup kernel to boot from you can boot in Fail-Safe mode:

When you boot the system in fail-safe mode, your configuration settings
are ignored. All kernel tunables are given fail-safe values and no kernel modules are
dynamically loaded during boot.

To boot an Integrity system in fail-safe mode, get to the HPUX prompt and enter:
HPUX>boot –tm
To boot an HP 9000 system in fail-safe mode, get to the ISL> prompt and enter:
ISL>hpux –tm
Some HP 9000 systems that have been updated from earlier versions of HP-UX have
boot loaders that do not support the -tm option. On those systems, enter the following
instead:
ISL>hpux –f0x40000

Once the server starts booting it will give you a message similar to this one, and it will boot in single user:

WARNING: The system has been booted in failsafe mode. All kernel tunable
parameters have default values. No loadable kernel modules are
in use.
NOTE: The kernel configuration that was in use when the system shut
down has been saved under the name 'saved_4b66b04a', in case it
is needed. If it is not needed, it should be removed (with
kconfig -d) to save space.

saved_4b66b04a is the name of your old kernel that has problems booting you can rename it, modify the parameter that was giving you problems and load it again.

It's not recommended to go to multiuser directly from a failsafe boot, it's allways better to fix the kernel problem and then boot from it.