DS25 and SDLT III tape drive

[nipun_2]

Hi,
I have DS25 Alpha Server and an external SDLT III tape drive attached to the vertical SCSI controller on the Alpha Server. This SCSi controller is NOT a card and is directly attached to the motherboard.

O.S: OPenVMS 7.3-2

This is the history
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=1153816


We did the following
1) attached a new terminator pin
2) Swapped cable with an existing DLT Iv tape drive
The Parity errors still persisted. We eventually looked at the system error logs with HP support and it was analyzed that the problem lies with the controller and therefore motherboard would be replaced.

In the interim period I considered an additional step to check this theory.

3) I moved the tape drive from the main server (we have 3 DS25s) to machine 1 (again a DS25) now the tape drive worked fine for few days and again today when I tried to Initialize a brand new tape I got parity error.

When I reported this to support I got a reply stating that this controller is not suitable fo r SDLT tape drive and we will have to buy a card

Part numbers provided:

3X-DEPVZ-AA
3X-KZPCA-AA
3X-KZPEA-DB

Now I discussed this with my vendor who had originally supplied this system. He checked out documentation but could not find anything to support this theory. Furthermore the vendor has also supplied the same configuration (DS25 + SDLT III tape drive ) to about 20 other customers and no complaints upto this point.

I have requested for a documentaiton that supports the "card" theory. If that solves the problem it is great however I do not wish to go on a wild goose chase...(already has been going on for more than 3 months now)

Your opinion/experience in this matter would certainly be very helpful.

[Hoff]

If you're not interested in chasing a few (more) geese around, you're probably not in the best spot when you post here in ITRC.

Have you communicated your concerns here along to the duty manager at the HP customer support center?

For added geese to chase, try gearing down the speed of the controller, as a start. There's a console environment variable typically available. And how long is this cable? The longer a SCSI bus is extended, the worse the configuration. Running the bus more slowly is a way to reduce exposure to problems; to mask an error.

Do consider answering Guenther's question from the other thread; what's the software involved here?

Are the current ECO (patch) kits for OpenVMS Alpha V7.3-2 installed on this particular box?

As for the suggested fix, a replacement SCSI controller can be pretty cheap. Assuming you have a slot open.

The other option is to bring in somebody from the outside to have a look at the box. As your profile indicates the UK, I can make some suggestions for folks based in the UK that deal with this sort of thing. Contact me off-line for a couple of contact names. (But then, that add-in SCSI controller might be the cheapest fix here.)

Regardless, I'd likely start with a call to the HP duty manager.

Stephen Hoffman
HoffmanLabs LLC

[John Abbott_2]

Hi nipun,

I can't comment on the other parts provided but I can confirm that a KZPCA in a DS25 connectnig an SDLT drvies is supported (for us) and works.

This was the solution we opted for a few years back with one of our DS25's, also running 7.3-2. I've had no operational issues with the configuration.

Regards
John.

[nipun_2]

Hello Hoff and John
thank you for your response. I intend to resolve the problem. What I meant by wild goose was not to go on random unsupported theories which unfortunately has been the problem with support (not with the forum where detailed explanation is also provided along with the solution).


some additional information I have gathered in the meantime is the following

This configuration (DS25 with SDLT has been running on more than 20 other setups at different locations. This information has been provided by the vendor.

I also received an additional call from Hp support stating that the tapes are the real culprit here. Even though I use brand new tapes the SDLT are particulary prone to errors. They would have servo track error

======
Based on the analysis the main issue lies not in the controller but the SDLT tape itself. In spite of having a new tape the theory has been that particularly SDLT tape is prone to â servo track damageâ resulting in parity errors.



The conclusion therefore is that even though the controller is not supported to run the SDLT tape drive it is not the cause of the problem. This is supported by the fact that there are several other locations running similar configurations successfully.

Future steps:

1) Order tape in batches of 10 or 20 to have a good quality packing due to vulnerability to errors due to jostling.

2) In future consider a LTO tape drive.


Anyone else who has experienced similar problems with the SDLT tape drives ???

[John Abbott_2 · Accepted solution]

Hi nipun,

> Anyone else who has experienced similar problems with the SDLT tape drives ???

We've quite a number of SDLT drives and had a few swapped out, ranging from tape unit faults to cable issues.

For HP drives use the LTT to check and update the drive firmware, we've had several problems with backups on the 75 firmware, latest is v95.

Finally, keep the unused tapes in their boxes and don't clean the drives unless asked (a common mistake) !!