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Tape DLT poor

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Arturo Mtz
Occasional Advisor

Tape DLT poor

hi

I have a DLT library working with OB2 3.0. Now, i see in Device & Media Manegement menu of OB2 Main, a poor condition in a configured media pool. by doubled-click on it i see the Media Management Menu and find it a Media with poor quality.
is posible to recover the data in it?
How i do it ?

Thanks
criminal
13 REPLIES
Joseph T. Wyckoff
Honored Contributor

Re: Tape DLT poor

I think most of the Omniback guys are watching in a slightly different forum (Openview Applications)

http://forums.itrc.hp.com/cm/CategoryHome/1,1147,163,00.html

Omniback may have decided the tape is poor for one of three common reasons...

1. Some sort of error interrupted a backup and restore. Often this is an I/O error.

2. The tape has been used a great deal, and Omniback has counted those uses, and decided the tape is OLD - and therefore should be taken out of use, even if it is working well at the moment.

3. The tape is in fact poor (which would result in I/O errors.)

Ask yourself which of these is most likely.

If there were I/O errors of some sort - look to remove that cause.

If you do not have a current set of Omniback patches, please get them - have them available, and apply them at some future point. The media agent patch is most relevant to your symptoms, but you should probably keep all of them reasonably up to date.

As an Omniback guy - I think of I/O errors as almost everything between Omniback and the magnetic tape. You should look to SCSI patches on the OS, TAPE patches, etc., as well as firmware in any fiberchannel MUXes, tape drives, tape libraries, and so forth.

Back to your question. If the tape is marked as poor, tell Omniback to VERIFY the tape (re-read the whole tape.)

If the tape verifies succesfully (and it isn't too old) then Omniback will mark it as FAIR again.

Good Luck.
Omniback and NT problems? double check name resolution, DNS/HOSTS...
Joseph T. Wyckoff
Honored Contributor

Re: Tape DLT poor

If the tape does not verify, but the hardware is good, patches a re good and so forth, then get ready to throw the tape away.

Actually it MIGHT be possible to recover data from the tape.

Exercise your ingenuity, perhaps the read (and verify) fails in one tape drive, but works in another...

If you really need to do so, you can use the unsupported TapeAnalyser tool.

Depending on what the problem is, there may be some other ways to get some of the data off. If this is a critical recovery, open a call.

Good Luck.
Omniback and NT problems? double check name resolution, DNS/HOSTS...
Dave Wherry
Esteemed Contributor

Re: Tape DLT poor

I've never used it, but, isn't there an OmniBack feature to make a copy of the tape?
Try to copy it to another good tape. If it works you have your data. Then you can do an init on the poor tape and most of the time it will come back as good again. First try to get your data off of it.
DLT tapes have such a long service life, many, many uses. Not to say it will not happen, I just have not seen any good bad and not be recoverable.
Arturo Mtz
Occasional Advisor

Re: Tape DLT poor

HI

I verified tape, and these messages appears:

Cannot read from device (I/O error).

Medium format corrupted, medium is not recoperable..

are there any form to recover data ?

thanks
criminal
Joseph T. Wyckoff
Honored Contributor

Re: Tape DLT poor

There is an unsupported utility called TapeAnalyzer you can try. You can use it to read the tape, get a list of files stored on the tape, and recover them by name. This can be tedious, and depending on what is really broken, simply may not work.

If you are really a brave soul, you may be able to use a utility like dd to bring the structure onto a disk and poke around in it.

That sort of recovery is probably better left for folks that do data recovery. Do a search for data recovery and you will find many companies that can attempt it for you.

A key point to observer is WHEN did it give you errors...If it verified for an hour before you got errors, then perhaps much of your data is intact. If it broke immediatly I would hold less hope.

Good Luck.
Omniback and NT problems? double check name resolution, DNS/HOSTS...
Tommy Brown
Respected Contributor

Re: Tape DLT poor

I have several"poor" tapes in my pools, I can still use them up until the point of "failure".
I cannot copy them, but if the data is in the catalog, it is retreivable.
Tommy
I may be slow, but I get there !
Jennifer Chiarelli
Regular Advisor

Re: Tape DLT poor

It never hurts to run a cleaning tape through the drive, if you haven't done so already.
It's a binary world!
Arturo Mtz
Occasional Advisor

Re: Tape DLT poor

HI

Where i can get TapeAnalizer and documentation ?

Does dd need any special option ?

I tried with some combination of block size but unsuccesfully.

Thanks
criminal
Joseph T. Wyckoff
Honored Contributor
Solution

Re: Tape DLT poor

/opt/omni/sbin/utilns/TapeAnalyser

There is no documentation that I am aware of - although if you execute the command it will give you a short syntax description.

I suspect you should probably give this task to a consultant or disaster recovery firm.

Good Luck.
Omniback and NT problems? double check name resolution, DNS/HOSTS...
Tommy Brown
Respected Contributor

Re: Tape DLT poor

the format of the data is encoded. Omniback has a special format that it uses to write the tape. It writes in 150MB (default) sections, but the data is encoded or encrypted via an omniback algorithm. I really am not sure that DD can move the data from tape to disk back to tape and still be readable by omniback..
Tommy
I may be slow, but I get there !
Arturo Mtz
Occasional Advisor

Re: Tape DLT poor

HI

I probed TapeAnalizer .
"timex /opt/omni/sbin/utilns/TapeAnalyser -device /dev/rmt/1m -list"
The result was both core file and error message :
"Number of active DA is bigger than allowed
Command terminated abnormally.

Thanks
criminal
Arturo Mtz
Occasional Advisor

Re: Tape DLT poor

HI Now i'm reading the tape with TapeAnalizer, the command was:
"timex /opt/omni/sbin/utilns/TapeAnalyser -device /dev/rmt/1m -comp_encr -recdmp -catalog -rechdr -blkhdr"

When this command terminate, i'll try to recover data.......

Thanks
criminal
Arturo Mtz
Occasional Advisor

Re: Tape DLT poor

HI

I can recover data from TAPE with the command

"timex /opt/omni/sbin/utilns/TapeAnalyser -device /dev/rmt/1m -filename /comercia
l/desarrollo/scepe003/respaldo/scepp003a.4gl -newfilename /temporal/arturo/recup
era.prueba2"

Thanks a lot for your help

I can restore my files from my DLT's with your tips

Regards to all !!!
criminal