boot from CDROM + LVM commands

[FTSE SysAdmin]

Hi,

I'd need a big hand of help with this issue :)

I got a system that had 2 swap devices (one on internal disk and 2nd swap device in a SAN - EVA5000). Both devices had priority 1.

In order to gain some space on the internal disk, I made a mistake of removing the swap device (on then internal disk leaving the SAN swap device as primary swap device). For my horror, once reboot the system the boot panic because was unable to recognize the swap space at boot phase. (Good shoot at the foot, I know).

However now I got a server unable to boot with one swap device configured to use SAN (useless)... the only way to access it is to boot from CDROM to recreate the swap device on the internal disk.

My 1st question is:

How to boot the CDROM with LVM commands? I boot from the CD but I've been unable to find a way to have the LVM commands available.

Many thanks

[Rodney Hills]

When you boot from CDROM, I assume you are in single user mode. Do a "mount /usr" to get access to the /usr/sbin folder which has the lvm commands.

HTH

-- Rod Hills

[Stephen Keane]

When you boot, interrupt the boot sequence, boot from the CD-ROM. When asked if you want to interact with ISL anwer y.

Then at ISL prompt type

ISL> hpux -lm

Which will boot you into LVM maintenance mode. You can mount /usr if you want, but there are statically linked copies of the LVM utilities in /sbin

[Raghu Chikkamenahalli]

You can use hpux -lm at isl prompt. and you can lvlnboot command.

[Florian Heigl (new acc)]

I think You can fix this easily by booting to LVM maintainance mode.
(hpux -lm)

active vg00, and then either remove the fstab entry and edit lvlnboot settings to reflect the current state or (definitely the healthier choice) re-create the swap space.
You'll need it for system dumps when the san is unavailable.

[FTSE SysAdmin]

for all the above replies.

The (hpux -lm) option is only available for boot disks but not for install cdrom/DVD.

Using the cdrom, the steps are:

get into recovery then shell (8Mb ramdisk)

then loadfile the lvm commands that you need.

Now a BIG problem...

Current HP-UX11i (11.11) install CDs only provide 8Mb of ramdisk. (HP look at this!!! JUST 8MB??? are we in 1985 or in 2005?)

Therefore you can only do one of the 2 things: or load some lvm commands or load the commands to fsck the FS and mount the FS in that ramdisk. (But not both because 8mb isn't enough for all commands)

So either way recovering and repair LVM on system that doesn't boot using the CDROM recovery shell IS SIMPLE IMPOSSIBLE.

HP now claims tha ramdisk isn't supported and their producedure (on recover manual) which supposed to increase the ramdisk from 8Mb to 32mb (sufficient to load the lvm commands and correct and mount the file-systems) isn't correct.

So if you ever want to repair a server with LVM (which you can't boot) you simple are stucked **avoiding to write other word here**.

Re-install the OS from scratch is the choice that I've chosen after spending 1 day and half trying to pass through all the issues with 8mb ramdisk provided by the "HP-UX Recovery CD" (Install CD)

:(

[FTSE SysAdmin]

.