topic Re: problem with lvol in Operating System - HP-UX

problem with lvol

Steve Dorland_1 — Wed, 13 Apr 2005 17:44:12 GMT

I have a system that seems to have a bad lvol, or bad disk. I brought it up single user and commented lvol5 (/opt) out of fstab, and then booted normally.

An lvdisplay of lvol5 seems to see nothing wrong, status available/syncd, all extents current, etc.

Sam reports lvol5 as "Unused".

"dd if=/dev/vg00/lvol5 of=/dev/null bs=1024k" just hangs... it never completes, no error messages or anything. I have to cycle power.

"fsck -F vxfs -o full,nolog /dev/vg00/rlvol5" also just hangs, after pass4. It doesn't error out, it just never returns. I thought that since Sam seemed to see it as unused that maybe I should omit the "-F vxfs", but it does the same thing, just hangs. Unable to break out of this also except by cycling power.

Can anyone help with where I should go with this?

Thanks!

Re: problem with lvol

A. Clay Stephenson — Wed, 13 Apr 2005 17:54:02 GMT

The first thing to try is a dd reading the entire raw disk (e.g. dd if=/dev/rdsk/c0t6d0 of=/dev/null bs=1024k). If that works the disk is okay. The next thing to try is your dd but this time use the rlvol5 device node instead of the block lvol5 device node -- I don't think this is going to work. If you are very fortunate, it's the LVM data structures that are corrupt rather than the drive itself. In that case, you can remove lvol5 and recreate it, build a filesystem, and restore /opt from backup.

Re: problem with lvol

Abhijit P. — Thu, 14 Apr 2005 00:21:30 GMT

Hi Steve,

I suppose the Data Structure of your lvol5 has been currpted or may be there are some bad blocks on the disks as you are saying in dd and fsck it hung..cause dd does a raw copy device to device so I would suggest if you have a tape backup of the volume you can remove and recreate it if it dosent work I think you should replace the disk by taking a Ignite first

Regards,
Abhijit

Re: problem with lvol

Steve Dorland_1 — Thu, 14 Apr 2005 09:49:08 GMT

Clay,

the dd on the whole raw disk behaves the same way, i.e. it just never returns. Doesn't error out or anything. I did "dd if=/dev/rdsk/c3t6d0 of=/dev/null bs=1024k" when I left last night and it's still sitting here this morning.

Steve.

Re: problem with lvol

Suraj Singh_1 — Thu, 14 Apr 2005 09:50:46 GMT

This indicates there is disk problem. Hope u have the backup of the lvol..

Change the disk and restore the data.

rgds

Re: problem with lvol

A. Clay Stephenson — Thu, 14 Apr 2005 09:59:50 GMT

The technical term for your situation is "toast". Of course, I'm sure that you have a recent make_tape_recovery tape handy because you are going to need it. This is also the reason that your should always mirror vg00; you wouldn't really have a problem at all now if that were the case.

Re: problem with lvol

MarkSyder — Thu, 14 Apr 2005 10:04:52 GMT

In my experience, the time to tell the men with the money you need MirrorDisk is just after an experience like this. They see it as a waste of money until just after it could have saved their skin.

So this is your big chance to get some money spent.

Mark Syder (like the drink but spelt different)

Re: problem with lvol

RAC_1 — Thu, 14 Apr 2005 10:13:55 GMT

As Clay explained, do you have backups ready?? Else, you can try mount the lvol in read only mode, and try to copy all you could to some other FS/tape.

Anil

Re: problem with lvol

Steve Dorland_1 — Thu, 14 Apr 2005 10:23:49 GMT

Ok, thanks all for your timely responses and confirmation of my toatiness...;( We do have backups... looks like I'll be going that route.