DLT8000 firmware issues?

[ITeam]

Customer has 4 DLT8000 drives, each on dedicated SCSI controller, on N-Class server running HP/UX 11.00.
2 of the drives are writing at about 150Mb/Min and 2 write at around 444Mb/Min. The "slow" drives have firmware 80 and the "fast" drives have f/ware 40 (or 44?).
Anyone know if a UX patch is required to match the later rev. of firmware on the "slow" drives?
Thanks! Paul.

[Vincent Farrugia]

Hello,

I don't think it's a firmware issue. Check whether the tapes are DLT III in the slower servers' drives. They are slower than DLT IVs.

HTH,
Vince

[ITeam]

Thanks Vincent - but I know categorically that all the tapes are DLT-IV type. Customer is now trying to arrange for firmware downgrade by HP (as it was HP who upgraded it in the first instance!).
Paul.

[Vincent Farrugia]

Hello,

Keep us informed about things after you downgrade.

[David Ruska]

Paul,
Judging from the firmware numbers (80 and 44), I assume these are standalone DLT drives (with V44 or V80 firmware). The V80 firmware provides an important fix for a potential data corruption issue, so I would not recommend downgrading. Was the change in performance directly associated with the update in firmware? If not, what HBA types are each of the drives on? Can the drives be moved to see if the problem follows the drive or the HBA? Also, can the media in "good" and "bad" drives be swapped, and the problem stay with the drive?

[Sanjay_6]

Hi Paul,

Check the controllers you are using to conenct the DLT's. Different controllers may give different performance using the same model of backup device,

Also, install the DLT 8000 pacthes on the box. Do a search for individual patches in the hp-ux category and use the string as DLT 8000.

hope this helps.

Regds

[ITeam]

Thanks all!
For David: Yes they are standalone units and problem only apparently appeared since HP swapped out 2 faulty drives ... the replacement drives have the later firmware on them.
For Sanjay: They are all on dedicated, identical controllers.
* As for patches ... there do seem to be several available ... I'll get customer to ask HP engineer why it's not occurred to them to check the patches that may be required and also maybe arrange to get the latest full set installed.

[David Ruska]

Paul,
You mentioned that the problem occured with the replacement drives with new firmware, so the performance issue could be the drives themselves OR the firmware version. You could downgrade the drive firmware and see if that fixes the problem. The easiest way do do this would be to move the drive to a windows system, and use HP Library & Tape Tools software (www.hp.com/support/tapetools). The V44 firmware can be obtained directly through the tool (if the system is web-connected), although HP would need to provide a password to enable firmware downgrading. For a password, either call the HP support center, or you could send an email to ltt_team@hp.com. Alternately, you could use the Support Tools Manager tool on HP-UX, although it would also require you to obtain a password for downgrading, and the firmware is file is not available directly, and HP would need to provide it to you manually.

[ITeam]

Okay guys - We are now certain it's the firmware - HP replaced rev.80 drive with unit on old rev and it's back to around 400MB/min backup speed. Now await HP comment about replacing the other rev.80 drive unit - or providing patch details.
* I'll keep posting updates as I get more info - might save someone else having the same problems.
Paul.

[Vincent Farrugia]

Hello,

Replacing the drive with another other in lower firmware version is not the same as downgrading the actual drive in question. It could be that the new drive has some settings which the old drive hasn't, which could answer the performance issues.

A question: Are the slow drives using hardware or software compression? This article:

http://www.hp.com/cposupport/information_storage/support_doc/lpg50030.html

states that "In almost all cases your overall backup performance will be better using the hardware compression. Performing a backup will already be very intensive on your system resources (CPU, Disks etc), and using the server to perform the compression will add to that system load. By contrast in the tape drive, there is a dedicated section of the hardware designed specifically for compressing and un-compressing the data without restricting the throughput."

HTH,
Vince