topic bad block on boot disk in Operating System - HP-UX

bad block on boot disk

Thomas F. Blich — Wed, 22 Nov 2000 13:41:57 GMT

I have a bad block on the boot disk. I have mirroring software, but unfortunately this disk was not mirrored before the corruption happened. If I enable the mirror for this disk, it never copies over one of the extents and keeps it as stale. My question is, if I replace the bad disk, will it rebuild it from the mirrored disk, or do I have to reinstall the OS? I was going to shutdown the server, put in new drive. Boot into single user mode off the mirror with the stale extent.

pvcreate the new drive
vgcfgrestore -n /dev/vg00 /dev/rdsk/ndew_drive

vgchange -a y /dev/vg00

reboot the server.

Does anybody know if this will work. I really don't want to go through a OS installation on this server.

Thanks,
Tom

Re: bad block on boot disk

Ruediger Noack — Wed, 22 Nov 2000 13:58:06 GMT

Hi Thomas,

may be it worked.

But first I would try to create a Ignite-Tape:
make_recovery -A

In case your plan doesn't work this would be your second chance for rebuilding your boot hd.

Good luck
Ruediger

Re: bad block on boot disk

Steve Massey_1 — Wed, 22 Nov 2000 13:58:31 GMT

might be worth finding where the stale extent is in the LV's

use lvdisplay -v and also pvdisplay -v

if it's in an unimportant VG - you may be ok -

you need to establish where your loss of data is

Re: bad block on boot disk

CHRIS_ANORUO — Wed, 22 Nov 2000 13:58:50 GMT

Hi Thomas,

That is the essence of having disk mirroring. Do as you have stated, restore with the good disk, you don't have to be afraid of OS reinstallation. I will also advise that you install Ignite UX as well amd make revovery boot tapes.

Re: bad block on boot disk

Dan Hetzel — Wed, 22 Nov 2000 14:02:44 GMT

Hi Thomas,

It is worth trying anyway.
I believe that making a recovery tape would be a good idea.
If you succeed booting of the new disk, you may try fixing the old disk with mediainit, but it will most probably need to be replaced.

Dan

Re: bad block on boot disk

Tony Constantine_1 — Wed, 22 Nov 2000 14:03:43 GMT

With one stale extent the mirror disk is no good.

Make an ignite backup of system disk, replace faulty disk, restore to new disk after booting of the ignite tape

Re: bad block on boot disk

Rita C Workman — Wed, 22 Nov 2000 14:05:52 GMT

Well I think you would have to include the vgsync command to copyback the mirror to the primary...
BUT....
here's a couple thoughts. There is a mechanism where LVM will store the data at the end of the disk, if it encounters a bad block. That is provided Bad Block Reallocation is turned on. However, this does not apply for root, swap or dump logical volumes.
So if you can confirm where/what is bad...you may be ok. If not, I'd take the cautious road.
If you have a make_recovery tape, I'd make use of it or I would bite the bullet and reload my OS

Just a suggestion,

Re: bad block on boot disk

Victor BERRIDGE — Wed, 22 Nov 2000 14:15:43 GMT

Re: bad block on boot disk

Stefan Farrelly — Wed, 22 Nov 2000 14:42:53 GMT

If you try to extend the mirror and cant (still have at least 1 stale extent) then the mirror copy is useless. You possibly wont be able to boot of it (depending which lvol the bad block is on) and if you could you possibly have a corruption on it where it couldnt copy from the original so its not advised to try this.

Replacing the disk is not advised until you make a backup. Using ignite to make a bootable tape backup is the best method. However, when running the make_recovery watch out for any errors which could be caused by ignite trying to read the bad block and failing - which may possibly result in your ignite tape being no good also. If the ignite tape is ok, replace the faulty disk, boot off the ignite tape and restore. This is the fastest and safest way to fix your problem (quicker than an OS reinstall).