altering init level

[amit mehta_2]

hi,
will altering the
init:3:initdefault: to init:1:initdefault:
in /etc/inittab file will change the run level persistant across reboot?

thanks,
amit

[Steven E. Protter]

Shalom amit,

This will cause the machine to boot up in single user mode, without networking and without mounting any filesystems.

It will make the system only accessible from the console(GSP/MP/iLo should work).

SEP

[freddy_21]

yes you will run at init 1. but at init1 all file system already mount, but network not running.

Diferent with single user mode. At single user mode all file system will not mount.


Thanks
Freddy

[Mridul Shrivastava]

Single user mode is used for maintenance purposes as there are some activities which can't be performed when system is running in level3 (or say multi user mode).

[amit mehta_2]

thanks steven,
As you said, the machine is now accessible only from the console now, but i can still see the entire file system mounted:-)
i know the following command at ISL promt will bring me into single user mode:
"hpux -is"
but will it be persistant across reboots?
do we have any environment variable which can return the run level?

thanks,
amit

[amit mehta_2]

hi,
figured how to find the run level.
# who -r
. run-level 3 Jul 10 11:57 3 0 S

thanks.

[Bill Hassell]

Just a note about single user mode:
init cannot take the system to a true single user mode, defined as no mounts (except / and /stand), no networking and other daemons. Despite tha man page concerning init s/S (and the man page for shutdown), this has not worked reliably for more than 10 years. The only guarenteed way to enter single user mode is to reboot and interrupt the boot process when it says you have 10 seconds. shutdown 0 was a really good way to bypass the (often lengthy) selftests going from an active run level to single user mode, but alas, filesystems remain mounted and other non-essential processes are still running.

Note that on newer processors (N/L class and rp models), a feature called SpeedyBoot was made available (without a lot of docs) to turn off various selftests. The command to set SpeedyBoot options is setboot. Note that full selftests are automatically re-enabled if a RAM or processor error causes the system to crash and reboot.

[amit mehta_2]

Thanks a lot :-)