topic Re: question about single-user mode in Operating System - HP-UX

question about single-user mode

JLee_1 — Mon, 23 Oct 2006 08:24:12 GMT

Good morning, all -- Just a quick question about working in single user mode.

Over the weekend I made my first attempt at booting a system into single user mode, but once there I was unable to execute any commands. It was as if I didn't have a working shell to execute commands with from the command line. I ended up bumping up to init 2 (which did work), and just doing the work I needed to do from there. So I'm wondering -- is there an initial step that I'm missing to be able to work in single user mode?

Thanks in advance for helping out a newbie...

Re: question about single-user mode

Peter Godron — Mon, 23 Oct 2006 08:26:51 GMT

Hi,
did you mount all your required disks /usr /var /opt /etc
Without those no commands would be found.

Re: question about single-user mode

Calandrello — Mon, 23 Oct 2006 08:30:24 GMT

Friend procedure certain e the following one: it interrupts boot hpux initiates the S.O with flag - lm Apos the S.O to initiate executes the command vgchange -a y the y /dev/vg00 mount -a

Re: question about single-user mode

Bill Hassell — Mon, 23 Oct 2006 08:30:31 GMT

Single user mode has only two filesystems mounted: / and /stand. Therefore, only the commands in /sbin are available. However, one of the commands in /sbin is mount so you can mount the 3 most important filesystems:

mount /usr
mount /tmp
mount /var

Now you can use bdf and vi and all the more familiar commands. You can also use mount -a to mount everything but you'll get errors with NFS filesystems (NFS doesn't exist because networking doesn't exist in single user mode), so use mount -al

Re: question about single-user mode

Patrick Wallek — Mon, 23 Oct 2006 08:31:25 GMT

In single user mode you do not have any fileysstems mounted other than / and /stand. There are some commands available in /sbin.

Depending on what you what to do you will probably want to mount at least /usr and /var. /usr contains all of your commands and libraries. /var provides /var/tmp for temporary files.

You generally won't need /opt or /tmp in single-user mode but you can mount them as long as the work you are doing does not effect those LVs.

Re: question about single-user mode

JLee_1 — Mon, 23 Oct 2006 08:32:09 GMT

Ahhh... so your very first step would be to mount the file systems you need? Is 'mount' an intrinsic command?

Re: question about single-user mode

Patrick Wallek — Mon, 23 Oct 2006 08:33:34 GMT

Calandrello -- the '-lm' flag DOES NOT get you to single-user mode. '-lm' gets you to LVM Maintenance Mode. That is different than single-user mode.

Using the '-is' (hpux -is) initiates single-user mode.

Re: question about single-user mode

Steven E. Protter — Mon, 23 Oct 2006 08:36:02 GMT

Shalom,

lvm maintenance mode and single user mode are similar but different tools for different jobs.

The primary purpose of lvm maintenance mode is inherent in its name. The quorum requirement that volume groups have more than 50% of members present is not in place permitting you to work with the system.

Single user mode itself is very much like normal mode without networking when you run Bill's three mount commands.

Its a great way to work without having users around.
SEP

Re: question about single-user mode

Patrick Wallek — Mon, 23 Oct 2006 08:36:14 GMT

Yes, it is. Once in single-user mode you can do:

# mount /var
# mount /usr

And whatever else you need. If needed, you can specify '/sbin/mount' on the command line.

Re: question about single-user mode

JLee_1 — Mon, 23 Oct 2006 08:37:10 GMT

That makes sense. Thank you all for the quick responses...and for bearing with me!

(Thanks for that clarification as well, Patrick)

Re: question about single-user mode

JLee_1 — Mon, 23 Oct 2006 08:38:30 GMT

Thanks again, all --