topic Re: SDLT reliability in StoreEver Tape Storage

SDLT reliability

Steve Reece_3 — Mon, 15 Aug 2005 10:36:55 GMT

A mate of mine has a number of clients with HP SDLT tape drives, both 110/220 and 320 GB varieties. Whilst they had no problems with DLT, the SDLT drives have given them no end of problems.
One of his clients has had their drive replaced four or five times, along with media replaced by HP because of tape-edge damage.

Has anybody else had less than optimal performance out of their SDLT drives?

(The drive that the customer who's suffered so many replacements is at the current firmware version and is suffering parity errors on new, HP-supplied, Quantum tapes.)

Thanks in advance

Steve

Re: SDLT reliability

matthew robey — Mon, 15 Aug 2005 20:58:46 GMT

Steve,

yep, I've had to have an SDLT drive replaced 5 or six times.

Hp have blamed the tapes, however it is always the same drive that need replacing (I have 4),
and different tapes have been used.

The backup will run ok and then after a variable ammount of time (ie not always at the same point) the backup will fail.

Matt

Re: SDLT reliability

Peter Quodling — Mon, 15 Aug 2005 23:52:06 GMT

Saw some problem with SDLT's at one site a while back, however have been having issues with LTO's at recent site. It's all flakey and just a matter of knowing how to escalate with the Service folk.

Peter Q

Re: SDLT reliability

John Abbott_2 — Tue, 16 Aug 2005 01:30:31 GMT

Just to keep a balanced view... we have 10 320sdlt drives and have used Maxell, Quantum (mostly), Fuji & Sony type I tapes.

We've had no drive swap outs yet and have had about half of the drives since they became available (so a mixture of Compaq and HP badges).

About 6 of the 10 units are used daily.

I think the MTBF for SDLT media is the same as DLT.

Do you use a cleaning tape on the drives regularly? I've been told only to clean them when asked.

Kind Regards
John.

Re: SDLT reliability

Jeffrey Willemsen — Tue, 16 Aug 2005 02:04:32 GMT

It may well have to do something with some batches or manufacturers of the tape cartridges. I see a few drives every month that are brought in with afore mentioned problems (and diagnostics reports tape edge damage) while the drives work perfectly without problems when using another tape cartridge. SDLT itself seems reliable, some cartridges that were acting up did well again after degaussing them.

Re: SDLT reliability

DICTU OpenVMS — Tue, 16 Aug 2005 02:16:09 GMT

At my current site it depends. Once in a while a drive needs to be replaced. After that it runs fine for a very long time. We have about 8 MSL's with about 20 drive's. Most of them are used daily. We have set the MSL to autoclean and reserved 1 slot for the cleaning tape...

Re: SDLT reliability

Robert Atkinson — Tue, 16 Aug 2005 03:07:04 GMT

We have 2 SDLT libraries and 2 internal standalone drives.

In general, they've been better than previous drives (DLT III, DLTIV) but still do require the ocassional swap out or jammed tape.

Robert.

Re: SDLT reliability

Steve Reece_3 — Tue, 16 Aug 2005 03:47:29 GMT

As Matthew commented, the drives seem to work for a variable amount of time and HP are apparently saying that the fault is either with the media or with the drive.

For the client that's had four or five drives, no problems with the SCSI bus or the adapter are indicated. The client has had a brand new Quantum tape that has failed, the tape being replaced after the previous one suffered tape edge damage.

Re: SDLT reliability

Peter Quodling — Wed, 17 Aug 2005 05:30:18 GMT

Personally, my favourite tape devices are STK 9840/9940's but now that Sun Microsystems have bought storagetek - who knows.

A quote from a former colleague who worked in DEC tape engineering (TK70 etc) will always stick in my mind. He was asked at a DECUS what he thought of exabyte drives. Without blinking, he responded... "They are great for backups.... But terrible for restores...." Nuff said...

q

Re: SDLT reliability

Aaron Lewis_1 — Wed, 17 Aug 2005 09:16:16 GMT

Steve, we had been having a lot of difficulty with some of our SDLT drives. They were constantlly logging errors, around 50 errors on every backup(140GB.)About once a month one of them would fail, we even had one that needed to be replaced 3 times in a week! Our FE decided to replace the SCSI controller as well, even though there were no indications of any errors on the controller. Since then we have gone about 5 weeks without any issues, well tape issues anyway. We still throw a few errors with every backup, but now it's only 2 or 3 a night. The next SDLT we have that fails, I'm going to request a new controller too.

Re: SDLT reliability

Steve Reece_3 — Wed, 17 Aug 2005 09:29:18 GMT

That's useful Aaron. Something that I'd thought about but having been told that the errors were either due to the media or the drive, my mate discounted that.
Thanks!

Re: SDLT reliability

Cass Witkowski — Wed, 17 Aug 2005 12:41:11 GMT

There was an article about getting parity errors during backups or even backup hanging if the WSQUOTA and or WSEXTENT was too small.

Re: SDLT reliability

Teengh Hergh — Tue, 13 Sep 2005 11:23:05 GMT

We have 16 110/220 Drives and we are facing the same problem. We have been working with HP since November 2004. HP had replace all the drives, but the errors are still there. HP 2ndary FE think we have worn out cartridges even though the cartridges were less than 2 years old and they are used less than they advertised.

We recently ran Tape Edge Damage test for the new drives and 5 of the 16 replaced drives were failed.

Not sure where to go from here.

Re: SDLT reliability

Steve Reece_3 — Fri, 16 Sep 2005 03:32:58 GMT

Sorry that you seem to be getting the same problems Teengh. HP first and second line support are telling us that it's a media issue. How that helps when a brand new, HP supplied tape fails I'm not sure!

Re: SDLT reliability

Jeffrey Willemsen — Fri, 16 Sep 2005 04:13:08 GMT

With regard to the tape edge damage test: if it fails it does not mean the drive failed, the cartridge you tested with is at fault. Replace that one. The message was not entirely clear about that.

Re: SDLT reliability

Wim Van den Wyngaert — Fri, 16 Sep 2005 08:59:51 GMT

Have a MSL that is running for almost 3 years. No problems until now.

But I lost count of how many drive/controller replacements we have had for the DLT891.

Wim

Re: SDLT reliability

Harry Su — Tue, 27 Sep 2005 09:44:33 GMT

We also got endless troubles with HP SDLT tape drive. We bought two servers at the same time, one with DLT and another with SDLT. For two years we had no issues in that DLT drive, however, 3 replacements had been done to the SDLT tape drive (thanks to maintenance contract) and we did not see any improvements. We are still continuously having tape damage problem for every one or two month. I personally gave up calling HP for the replacement again. I believe it is a design problem and is impossible to resolve by changing tape device. Maybe it is the better way to change SDLT to another tape device.

Re: SDLT reliability

Jaclyn Rothe — Wed, 05 Oct 2005 19:00:15 GMT

The issue with SDLT drives is that the tapes are very sensitive to tape-edge damage. Shipping, and incorrect handling can cause TED.
Tapes with TED can bring down SDLT drives.
I recommend DLT drivs or LTO drives.

Re: SDLT reliability

Jaclyn Rothe — Thu, 06 Oct 2005 12:34:10 GMT

The best advice at stopping the endless circle of TED is to replace the tapes and the drive. The problem is if a tape with TED is inserted in a drive, it will cause drive issues. If you run the TED test with no tape in the drive it will deterine if the drive has tape edge damage. LTT will compile a log of tapes with TED, however it is not easy to determine which of these tapes correspond to with ID number.
If you run the TED test on the tape and it passes with no TED damage, then the tape should be fine, set it aside and try the next tape, and so on. Set aside the tapes that are reported as having TED, and dispose of them.

Re: SDLT reliability

Steve Reece_3 — Fri, 07 Oct 2005 04:11:41 GMT

Thanks Jaclyn. That makes sense.