DDS3 Fails to read DDS Tape

[Jennifer Chiarelli]

I have a L2000 server with a DDS3 4mm dat tape drive. We are attempting to read old DDS 60 meter tapes to restore data for a PDM database.
I have tried to read the tape using tar -tvf and by using the PDM data restore utility. Th ioscan -fnC tape shows:
Class I H/W Path Driver S/W State H/W Type Description
=====================================================================
tape 0 0/0/1/0.3.0 stape CLAIMED DEVICE HP C1537A
/dev/rmt/0m /dev/rmt/c0t3d0BESTn
/dev/rmt/0mb /dev/rmt/c0t3d0BESTnb
/dev/rmt/0mn /dev/rmt/c0t3d0DDS
/dev/rmt/0mnb /dev/rmt/c0t3d0DDSb
/dev/rmt/c0t3d0BEST /dev/rmt/c0t3d0DDSn
/dev/rmt/c0t3d0BESTb /dev/rmt/c0t3d0DDSnb
tape 2 0/2/0/0.3.0 stape CLAIMED DEVICE Quantum DLT4000
/dev/rmt/2m /dev/rmt/c8t3d0BEST
/dev/rmt/2mb /dev/rmt/c8t3d0BESTb
/dev/rmt/2mn /dev/rmt/c8t3d0BESTn
/dev/rmt/2mnb /dev/rmt/c8t3d0BESTnb
And lssf /dev/rmt/0m shows:
stape card instance 0 SCSI target 3 SCSI LUN 0 at&t best density available at ad
dress 0/0/1/0.3.0 /dev/rmt/0m
Do I need to take special steps to read a DDS 60 meter tape?

[Peggy Fong]

Lanny
I sure someone has better news for you than I do. It is my understanding that the dds3 cannot read 60Meter tapes....those are really old tapes.
Peggy

[Jennifer Chiarelli]

Peggy, thanks for the response! Can anyone else confirm this for me?

[Paula J Frazer-Campbell]

Hi

DDS drives were supposed to backward compatible ?? Although I have never tried it.

Are you sure that the tape is in tar format?

Try other formats ? fbackup cpio etc.

Paula

[Thierry Poels_1]

I agree 100% with Paula.
We sometimes use old DDS-1 tapes for small dumps, never had problems.
BTW DDS-4 will be the last in the line. HP & Sony are switching to new technology (hmmmz I don't mean NT ;)
regards,
Thierry.

[A. Clay Stephenson]

Hi Lanny,

Paula is correct, I keep an old DDS-1 drive around for just that reason; anyone can read it. DDS-1 can't read DDS-2 or DDS-3; but either DDS-2 or DDS-3 can read DDS-1.

Most likely you are having a blocksize problem or a byte swap problem.

I think the first thing I would do, is dd off a little bit of the file and have a look at it.

e.g.

dd if=/dev/rmt/0m bs=1024 count=2 of=/tmp/x1

Then do an od -c /tmp/x1 | pg.

Does any thing appear recognizable? Does it appear that every pair of bytes is swapped?

To correct byte-swapping:
dd if=/dev/rmt/0m bs=1024 conv=swab of=/tmp/x2

You may then have to adjust blocksize to match the original format.

When you're done; you might end up with a command that looks something like this:
dd if=/dev/rmt/0m bs=20b conv=swab | tar xvf -

Man dd for details.

Clay

[Peggy Fong]

I agree with everyone that tapes drives are backward compatible (not forward :)) but for some reason I thought the 60 meter tapes didn't work on dds3. Let us know if any of the suggestions work - I'd be interested in knowing if it does.

Thanks,
Peg

[Peggy Fong]

Lanny

I'm losing my memory in my old age. I did find a link to a tape drive support matrix - see: http://us-support.external.hp.com/cki/bin/doc.pl/sid=5c8f72121cecf12ecf/screen=ckiDisplayDocument?docId=200000054887074

Are you using /dev/rmt/0m for your tape drive?
What errors are you getting or symptons? Do you know what utility was used to write to the tape. All the suggestions above were good ones - hope one works.

Peg

[Bill Hassell]

60 meter tapes were often not DDS at all but audio tapes with awful error rates. That's why all DDS tape drives with Media Recognition treat 60 meter tapes as read-only. However, they should read reasonably well.

tar (and cpio and other classic Unix tools) have terrible diagnostics. HP's tar expects 10K records and gives no clue what the problem is when a different record size is used. Use pax instead of tar (which reads both tar and cpio) since pax adapts to different record sizes.

[Carlos Fernandez Riera]

For tapes wrote in older dirves see:


http://forums.itrc.hp.com/cm/QuestionAnswer/1,1150,0x171172106351d5118fef0090279cd0f9,00.html

[KapilRaj]

Hi ,

You had enough good answers . Let me add my contribution to this,

HP DAT Drives are classified mainly into two groups

The DDS series...... Comes with HP9000
The Surestore series.......Comes with HP Netservers (Intel based servers)

Both have 3 or 4 generations

2/4 GB ............ 90 metres ----DDS1.........Surestore 2000
4/8 GB ............ 90 /120 metres ........DDS2.........Surestore DAT 8 i
12/24 GB ........ 90 /120 / 125 metres ........DDS3 ..........Surestore 24 i

fourth one i hv'nt seen so far....
The first column is data capacity ,second catridges supported , third it's DDS member & fourth is it's surestore member.

Backups taken on DDS can not be read by Surestore & vice versa

The DDS3 can read/write DDS3 , DDS2 & DDS1
The DDS2 can read/write DDS2 & DDS1 not DDS3 and above
The DDS1 can read/write DDS1 not DDS2 and above

So in this case your catridge may be a surestore one. please confirm.
if it is so you can connect a surestore 4/8 GB or 12/24 GB Drive to your system & retrieve your data.

I never heard abt 60 metre catridges !!!! they are audio cassets !!!

Good luck

kaps

[Christian Schulze]

I had a similar Problem, my DDS3-Drive won't write an 60m Tapes (no Audio-Tape, they are labeled "HP DDS 60m") but they are readable.

I switched to DDS3 125m Tapes.

Christian