topic Re: Need HP-UX data recovery in Operating System - HP-UX

Need HP-UX data recovery

Kevin Heater — Mon, 30 Jul 2001 16:43:44 GMT

Here's the situation we were upgrading a J5000 from 10.20 HP-UX to 11.00 HP-UX and the installation quit while trying to build the kernel. After trying to recover the system with no success. we performed a cold 10.20 install which worked; however our "complete system backup" has been bombing out at night because no one ever put in a second tape after the first one was full (don't ask). Anyway during the reinstall and recovery of what data we did have backed up I pulled out the offline dirves which at one time had been a mirrored copy of the entire system. It is likely that one of the drives has been at least partially over written and the other is untouched. There is a 50-50 chance that the untouched drive has the LVM tables on it. Does anyone out there know of a company or individual which specilizes in HP-UX data recovery of partially corrupted logical volumes? or if HP providses this service. Please respond to this post or email at kevinh@tgstech.com if you can help.

Thanks in advance,

Kevin Heater

Re: Need HP-UX data recovery

James R. Ferguson — Mon, 30 Jul 2001 16:59:14 GMT

Hi Kevin:

One thought is a follows. Try 'vgimport'ing the volume to a pseudo, unique volume group as:

# mkdir /dev/vg09
# mknod /dev/vg09/group c 64 0x090000
# vgimport -v /dev/vg09 /dev/dsk/cXtYdZ

Then, having created directories for mountpoints, mount the logical volumes and look for the files you seek.

...JRF...

Re: Need HP-UX data recovery

A. Clay Stephenson — Mon, 30 Jul 2001 17:03:52 GMT

Hi Kevin:

What a tale of woe!.

I would at least try a vgimport something like this:

mkdir /dev/vg06
mknod /dev/vg06/group c 64 0x060000
vgimport -v /dev/vg06 /dev/dsk/c1t5d0 (or whatever device)
vgchange -a y -q n /dev/vg06

If you are lucky, you can then create mountpoints and mount the filesystems.

Clay

Re: Need HP-UX data recovery

Sachin Patel — Mon, 30 Jul 2001 17:24:24 GMT

Hi Kavin,
If you are lucky then Mr James and Mr Clay's way is the only way. But let me ask you this.
What if I have 32 vg's and around 60 physical disk on one system?
I had that problem last week when we lost root disk on our v-class. Luckly we had printing of /etc/fstab, vgdisplay of all vg's.

Sachin

Re: Need HP-UX data recovery

Kevin Heater — Mon, 30 Jul 2001 18:24:43 GMT

Just for clarification: Let's assume that I'm unluky and can import the volume group information using a vgimport command. Asuming that we need this data is there someone out there who can get it? Does hp, or maybe some third party consulting group do it?

Re: Need HP-UX data recovery

A. Clay Stephenson — Mon, 30 Jul 2001 18:45:04 GMT

Hi Kevin,

I been in the HP community for a number of years and I have never heard of a vendor that does what you are asking. Bear in mind, that if the data has been overwritten, noboby can get it back. I would certainly try the vgimport; it's really your best shot. If you get a good import you could mount the filesystems read-only to protect them from yourself.

The only other technique that has a prayer is to dd the raw disk and examine the file with od. You might be able to pull off pieces of (and maybe even whole) files that way.

Best of luck, Clay

Re: Need HP-UX data recovery

James R. Ferguson — Mon, 30 Jul 2001 18:57:08 GMT

Hi Kevin:

I don't envy your situation. If the 'vgimport' isn't workable, then I think you are SOL.

I find that good insurance during an upgrade, including cold-installing a new OS, is to first have a good Ignite 'make_tape_recovery tape' of the OS as it exists on the old boot disk. A backup of the boot disk (vg00) with standard utilities like 'tar', 'cpio' and 'fbackup' isn't much good if you have to create a viable vg00 from scratch.

The second thing I like to do is cold install to a new disk. I readdress the old OS disk to a lower, unused priority and address the new disk (to be) as the priority target. That way, when I'm done, and have a viable installation, I'm good-to-go.

None of this helps much now, but perhaps provides something for consideration next time. Good luck.

Regards!

...JRF...

Re: Need HP-UX data recovery

Dragan Krnic — Tue, 31 Jul 2001 08:47:24 GMT

Kevin, what type of file system was it on your disks hfs or vxfs. I have some experience in salvaging corrupt systems, if a) the hardware is accessible and b) the information IS there.