topic Re: Backup recovery from magnetic tape in Operating System - OpenVMS

Backup recovery from magnetic tape

Shelto Perry — Mon, 06 Dec 2010 11:47:04 GMT

If a backup from disk to tape is being peformed and if fails near completion, can I still recover data from this tape later on?

Error message:

%BACKUP-E-FATALERR, fatal error on $2$MGA1:[]DKRPTS.BCK;
-SYSTEM-F-VOLINV, volume is not software enabled
%BACKUP-I-OPERSPEC
%BACKUP-I-OPERASSIST, operator assistance has been requested

Re: Backup recovery from magnetic tape

Volker Halle — Mon, 06 Dec 2010 12:11:00 GMT

Shelto,

the data, which has been written to the tape prior to this error, should still be readable and therefore restoreable.

You could at least do a BACKUP/LIS $2$MGA1:DKRPTS.BCK/SAVE/REWIND to find out, which files has been saved.

Volker.

Re: Backup recovery from magnetic tape

Jan van den Ende — Mon, 06 Dec 2010 12:25:33 GMT

Shelto,

To begin with: WELCOME to the VMS forum!

Volker is right of course (as usual).

BUT!!

Maybe, just maybe, the tapedrive should be cleaned.

If in any way possible, repeat the save (to new tape).
Mark your failed tape for destruction, as soon as you have finished your repeated save.
It definitely is _NOT_ trustworthy!
Proost.

Have one on me.

jpe

Re: Backup recovery from magnetic tape

Robert Gezelter — Mon, 06 Dec 2010 13:47:54 GMT

Shelto,

I more or less concur with Jan and Volker, to the extent that IF the disk drive died immediately following the BACKUP, and all that I had was this not completed BACKUP, I would recommend a good, careful examination to see what we could recover. If (and that is a big IF) the file was already backed up before the tape error, it might be recoverable.

However, I would not rely on this tape as a backup copy unless it was an emergency. Get another backup as soon as possible, on a different tape (lest the new backup fail also, and also destroy the results of the last attempt).

I wholeheartedly endorse the comment about cleaning the drive, per the recommendations in the drive manual.

It is far easier to deal with these problems now, than it is to wait for later when they are far more serious.

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

Re: Backup recovery from magnetic tape

Shelto Perry — Mon, 06 Dec 2010 14:46:27 GMT

Thanks a million. I will try some of the suggestions.

Re: Backup recovery from magnetic tape

GuentherF — Mon, 06 Dec 2010 17:31:18 GMT

VOLINV means the tape could not be mounted foreign successfully. This is NOT an indication of something wrong with the tape media or tape drives read/write capability.

Given a device name of MGAnnn I assume a problem with connecting to the tape drive from OpenVMS.

To verify connectivity to the tape drive:

$ MOUNT/FOREIGN/NOASSIST MGAnnn
$ DUMP/BLOCK=COUNT:1 MGAnnn

/Guenther

Re: Backup recovery from magnetic tape

Jan van den Ende — Mon, 06 Dec 2010 18:08:26 GMT

Re Guenther,

>>>
This is NOT an indication of something wrong with the tape media or tape drives read/write capability.
<<<

Sorry, but I have to disagree. (that is, _IF_ the original statement is reliable
>>>
... fails near completion ...
<<<

Then usually somehow the tape or the unit "lost position", which with SCSI is "Fatal Error".

Question for Shelto: Did you get a "$2$MGA1: Mounted" message (either from an explicit MOUNT command before starting the BACKUP, or from BACKUP itself from its implicit Mounting?) It should be in your LOG if you still have that.

If not, Guenther may be right, but that does not chime well with your "near completion".

hth

Proost.

Have one on me.

jpe

Re: Backup recovery from magnetic tape

Shelto Perry — Mon, 06 Dec 2010 20:01:09 GMT

Message failure came at the end of backup had about 50 more files to backup before failure. I'm not able to mount/for tape drive to do a dump, so I incline to believe that the tape is no good.

Re: Backup recovery from magnetic tape

GuentherF — Mon, 06 Dec 2010 21:07:34 GMT

I don't see why your tape is "no good". VOLINV indicates a conenction problem between the host (VMS drivers) and the tape controller.

Any error from the tape drive regarding media problems would be a DRVERR. Any error in the tape controller would be reported as a CTRLERR.

"I assume" that if this really happened at the end of a backup we lost FC connectivity to the tape drive/controller.

/Guenther

Re: Backup recovery from magnetic tape

Shriniketan Bhagwat — Tue, 07 Dec 2010 03:36:55 GMT

Hi,

There are several factors causing SYSTEM-F-VOLINV error. It could be any one of the below.

1) The tape is already mounted by another process.
2) The tape is not loaded in the drive
3) The tape drive is offline
4) The drive is broken
5) A scsi (if is it a scsi device) address conflicts with drive's one.
6) The scsi controller is broken
7) The scsi controller conflicts with other peripherals.

Regards,
Ketan

Re: Backup recovery from magnetic tape

MichelleP_1 — Tue, 07 Dec 2010 06:29:50 GMT

Following up on Guenther's suggestion that it's FC connectivity...
-------
Are all of the paths reachable? You hope NOT to see "not responding" on any paths.
$ PIPE SHOW DEV/FULL MGA | SEARCH SYS$PIPE MG,PATH
--------
Try SCSI_INFO:
$ scsi :== $sys$etc:scsi_info.exe
$ scsi $1$mga1
--------
Check the port statuses in SDA:
$ show dev fg
$ anal/sys
SDA> fc set dev FGA0
SDA> fc name

Look for port(s) beginning with 5005, you hope to see "VALID" state, not "PAUSED" state.

Repeat SDA commands for each FG device.
--------
If your tape drives/libraries are DLT IV and connected to FC through an MDR*...
To cycle power on the tape drives and MDR:
1. Power off tape drive(s) and MDR
2. Power on tape drive(s)
3. Wait until tape drive(s) are completely up and ready
4. Power on MDR

*My experience is with DLT IV tape libraries and an MDR. These are older technologies. I'm not sure if it's the same process for newer tape drives/libraries.
------

Sorry I can't give you actual examples. I don't currently have any MGA devices, but in the six years I was at a site that did, I can't tell you how many times I had to go through these processes.

Regards,
Michelle

Re: Backup recovery from magnetic tape

Jan van den Ende — Tue, 07 Dec 2010 08:28:02 GMT

Michelle,

>>>
but in the six years I was at a site that did, I can't tell you how many times I had to go through these processes.
<<<

I definitely share such memories!

I just do not recall the exact message...
Guess I just pushed those ugly memories out of my working set :-)

Proost.

Have one on me.

jpe

Re: Backup recovery from magnetic tape

GuentherF — Tue, 07 Dec 2010 17:07:28 GMT

Ketan,

not quite:

"1) The tape is already mounted by another process." -> Error is DEVALLOC

"2) The tape is not loaded in the drive" ->
Error is MEDOFL

"3) The tape drive is offline" - As far as I can remember there is no VMS OFFLINE state for a tape drive - like for some pseudo devices which would return DEVOFFLINE.

/Guenther