topic Re: Volume set repair in Operating System - OpenVMS

Volume set repair

Michael Purdy — Fri, 06 Jan 2006 11:53:37 GMT

We have a 2 node cluster VMS 7.2-1 and 2 volume sets. 2 disks were removed from a volume set and used elsewhere. Is it possible to repair the volume set to continue without the 2 disks. The mount command fails with failed to lock volume and device is not mounted. I do not think the disks were removed cleanly from the vol set, any ideas?

Re: Volume set repair

Wim Van den Wyngaert — Fri, 06 Jan 2006 11:58:04 GMT

Never used volumesets but to my knowledge you can not repair it.

Wim

Re: Volume set repair

Ian Miller. — Fri, 06 Jan 2006 12:02:20 GMT

I think it's time to test your recovery strategy - do you have a backup?

How many disks in each set?

The problem is that some or all of each file would have been on the disks that where removed.

Re: Volume set repair

Jan van den Ende — Fri, 06 Jan 2006 12:17:17 GMT

Michael,

Sorry, but NO way! Part of your data (about 2/3) is (was) on the disks that are used elsewhere.
And if you find a single drive big enough to hold all, even a restore to that drive is not straightforward. An /IMAGE restore WILL want to restore each file(-fragment) to its original Relative Volume Number.
_IF_ you had _NO_ file aliasses on that set, _THEN_ you can restore the whole saveset to a mounted Files-11 drive. Make sure not to forget /OWN=ORIGINAL !

I wish you good luck and success. I think you will need both.

Proost.

Have one on me.

jpe

Re: Volume set repair

Robert Gezelter — Fri, 06 Jan 2006 17:44:33 GMT

Michael,

Obviously, the data on the two volumes that were removed is lost (presuming that they were overwritten).

It may be possible to recover some of the contents of the remaining volumes (actually, I told a war story about just such an incident at the 1990 European DECUS Symposium).

I am in the middle of something, I will try to comment more extensively later.

- Bob Gezelter, http://www.rlgsc.com

Re: Volume set repair

Michael Purdy — Mon, 09 Jan 2006 09:20:13 GMT

Thanks for the inputs. Could be a case of RTFM for Volume sets. At the moment I have a backup to restore, but would like to save the data on the remaining RVNÂ´s at this point if possible. I have tried mounting individual shadow sets (RVNÂ´s) but have the same problem as RVN 6 is not available. Surely it must be possible to mount and backup single RVNÂ´s, no? (IÂ´ve tried the /vol=n switch).

If not I have to init the Volume set and hope I can restore the original files to the smaller volume set...

Re: Volume set repair

Robert_Boyd — Mon, 09 Jan 2006 09:29:55 GMT

By reading the documentation on BACKUP and volume sets you will find the instructions for restoring a single member of a volume set from your backup. I believe the HELP for BACKUP has some information on this as well.

I haven't done this in years, but it is possible to just restore the missing volumes from your last backup.

You will have to provide drives of course.

If you want to back up the contents of the untouched members of the volume set before proceeding, you can always do a BACKUP/PHYSICAL of them for safekeeping.

After making a physical backup of them, you could try restoring just the 2 missing drives and mounting the volume set. If it will mount at all, then you can do a file level backup of the 2 good volumes by using the /VOLUME qualifier to specify which one(s) you want to select.

After backing up the files, then you can attempt an ANALYZE/DISK [/REPAIR] on the volume set and see just how bad things look.

Robert

Re: Volume set repair

Wim Van den Wyngaert — Mon, 09 Jan 2006 09:43:20 GMT

You can also copy-delete files that are already restored. To another disk that is.

Wim

Re: Volume set repair

Robert Gezelter — Mon, 09 Jan 2006 10:09:00 GMT

Michael,

Before doing anything else, take the surviving members of the volume set offline.

As I mentioned previously, it is possible to recover the data on the surviving members of the volume set.

Having done this very procedure (as a result of a head crash), it is doable (and ironically) fully within the Files-11 specification. However, it is delicate procedure, and involves faking out MOUNT and carefully using the results from ANALYZE.

If the data is valuable, it is worth doing. This is particularly true for very large volume sets (such as the one that you describe).

It is difficult to describe the detailed steps to recover this situation in a reasonable length posting, but it is possible to recover the files on the surviving volumes.

If I can be of assistance, please drop me a note by private email.

- Bob Gezelter, http://www.rlgsc.com

Re: Volume set repair

Michael Purdy — Mon, 09 Jan 2006 10:33:49 GMT

OK, so the Volume set was made up of 6x 2 disk shadow sets, 1 shadow set was removed. All the data is backed up. All the remaining disks have been dismounted. I have started to do a Backup /physical of $10$DKA0: of the first shadow set, and will take a backup of the other four disks too. then plan A is to init the volume set with the 5 shadow sets and restore the whole volume to this...

Re: Volume set repair

Jan van den Ende — Mon, 09 Jan 2006 10:46:59 GMT

Michael,

so you HAVE 10 disks?

I think you stand a much better chance, if you re-create a 6-volume set from 6 shadowsets, with 2 of those shadow sets being single-disk. (AFTER you finish the physical BACKUPs, of course).

That would mean that at the logical level you are re-creating the same configuration.

You sacrifice some redundancy (and perhaps some read-performance) but it _IS_ the same logical structure as the one you saved!

And after you get that back on line, real quickly start planning how to get to full redundancy, and how to prevent this thing from happening again!

Success.

Proost.

Have one on me.

jpe

Re: Volume set repair

Robert Gezelter — Mon, 09 Jan 2006 12:28:49 GMT

Michael,

My preference here would be to disconnect one of each of the shadow sets (and reclone). I would then put the preserved members aside (phyisically).

You can then re-create the missing volume ONLY. The MOUNT will then work, albeit with any elements missing that were on the lost pack.

Recovering beyond this is a manual operation, involving the ANALYZE/DISK utility. As a starting point, you should not have to restore the entire volume set UNTIL AFTER there is an understanding of the degree of the damage.

Generally speaking, files created DO NOT, unless no space exists on the current volume, straddle members of the volume set.

- Bob Gezelter, http://www.rlgsc.com

Re: Volume set repair

Michael Purdy — Wed, 11 Jan 2006 05:27:00 GMT

The volume set was reinitialised and the data restored from backup...

Thanks, dank je wel, merci vielmal, for all replies.

-Mike