topic Re: lvm mode in Operating System - HP-UX

lvm mode

mukesh_a — Fri, 07 Sep 2007 18:24:46 GMT

can some body what is the differecne amon lvm single user mode , lvm maintenance mode and lvm quroum mode ,

Re: lvm mode

VK2COT — Fri, 07 Sep 2007 18:51:16 GMT

Hello,

Man hpux(1) would give you basic idea:

-lm Boot the system in LVM maintenance
mode, configure only the root volume,
and then initiate single user mode.

After you have made the LVM disk minimally
bootable, the system can be booted in
maintenance mode using the -lm option of the
hpux command at the ISL> prompt. This causes
the system to boot to single-user state
without primary swap, dump, or LVM to access
the root file system.

-lq Boot the system with quorum override
option. This option is used in a
scenario where a disk is removed from
the system or is otherwise unavailable,
but the corresponding entry for the
physical volume has not yet been
removed from the volume group using
vgreduce.

In LVM, when the root disk is mirrored, the
computer can only activate the root volume
group, which contains the OS instance, when
the majority of the physical volumes in a
root volume group are present at boot time.
This is called establishing a quorum.
Sometimes, you may want to boot an OS
instance regardless of whether a quorum is
established. You can override the quorum
requirement by using the -lq option.

Basiclly, these modes are your friends to
recover from various hardware and/or
Logical Volume Manager problems.

Cheers,

VK2COT

Re: lvm mode

whiteknight — Sat, 08 Sep 2007 10:50:29 GMT

The possible options are:
-is single user mode boot Activate vg00, mount only / and /stand, do not go through the startup script. So e.g. the network is not started and other users cannot login.

-lq quorum mode boot Same as single user mode but the root VG (vg00) gets activated even if the LVM quorum is not present, i.e only 50% or less of the disks are available. This option can be used if a mirrored root disk is defect.

-lm maintenance mode boot vg00 will not be activated. The root FS is mounted using the auxiliary device file /dev/root. In this mode you are able to export vg00 and perform LVM low level

if you have HP support contract, you can view this doc.

http://www1.itrc.hp.com/service/cki/docDisplay.do?docLocale=en&docId=emr_na-c01037092-1

WK
please assign points

Re: lvm mode

Steven E. Protter — Sat, 08 Sep 2007 13:10:59 GMT

Shalom,

lvm and single user mode are very similar, no networking, nothing mounted. lvm mode has some tools available that can permit you to solve problems. I've been able to use single user mode to solve disk problems as well, but lvm mode makes it easier.

Example. A volume group can not activate when a quorum, more than 50% of its members are not present. I once unwisely made vg00 a two member volume group, the second member being on a jamaica box. Turn off the jamaica box, or in my case clean the Israeli dust out of the things and I've go to quorum and can't boot.

So, I boot into lvm mode and take the second disk out of the volume group so the box will boot.

SEP