Problem With SDLT 320 Drive Reading DLT4 Tapes (34 Views)
Reply
Occasional Visitor
Paul_487
Posts: 3
Registered: ‎10-22-2004
Message 1 of 6 (34 Views)

Problem With SDLT 320 Drive Reading DLT4 Tapes

We have a MSL5026 library with SDLT 160/320GB drives installed using CA's BrightStor version 11 backup application. I am trying to read DLT Type 4 tapes that we backed up using our old TL891 Library. When I do this both BrightStor and Compaq Insight manager reports errors and the job is terminated. Sample errors are "Unable to position session trailer", "Unable to position media catalog file", "Unable to locate session". Insight Manger shows a red status on the backup server. I opened a case with CA and they had me setup the TL891 with the same version of BrightStor that I am using on the MSL5026 and I was able to read the type 4 tapes with no problem. The HP compatibilty matrix says the SDLT drive is read-only compatible but I can not seem to get that to work without errors. HP Library and Tape Tools diags show no problems with hardware. Please advise if you have any suggestions?

Thank you,

~Paul
Please use plain text.
Honored Contributor
Marino Meloni_1
Posts: 2,075
Registered: ‎08-23-2001
Message 2 of 6 (34 Views)

Re: Problem With SDLT 320 Drive Reading DLT4 Tapes

read compatibility is related to the hardware, that is why probably issuing a "media validation test" within L&TT give you no errors, but the logical compatibility depend on the way you write your data, writing with a software, do not mean you can read with all other software, even on the same drive.
If using the same version of sw to write on old dlt and read on the new sdlt solve your problem, this mean that the two versions of Brightstore are not 100% compatible.
You cannot blame your hardware for that
Please use plain text.
Regular Advisor
Cameron Todd
Posts: 172
Registered: ‎05-11-2004
Message 3 of 6 (34 Views)

Re: Problem With SDLT 320 Drive Reading DLT4 Tapes

While theoretically it is backward compatible, reading DLT IV tapes in an SDLT drive is very hit and miss in reality.

The best chance at restoring data from any given tape is by placing it in the same drive it was originally written on.

Some DLT tapes will read in an SDLT drive but many won't and it depends on the various alignments (or misalignments!) of the respective tape mechanisms, tape head density's, track positions etc etc.

(Sort of like reading 360k floppies in a 1.2Mb FDD!)

If you can read the tape in question fine in the older drive unit then the tape has obviously not gone bad and it isn't a backup software problem, but is purely a drive tolerance issue.

You need to keep your old drive so can access all the existing tapes when required.
Please use plain text.
Trusted Contributor
Stuart Whitby
Posts: 190
Registered: ‎10-18-2001
Message 4 of 6 (34 Views)

Re: Problem With SDLT 320 Drive Reading DLT4 Tapes

I think you should get back to CA on this one. If I'm reading your comments right, one version of their software can read this tape in this drive without problem and a newer version can't. If that's the case, this problem is likely to get more difficult to fix the longer it goes on - simply to find someone at CA who can remember the differences between versions in order to sort your problem out.

My guess is that they've "optimised" something while writing the later driver, without thinking about backward compatability. If you've got any legal requirements which require you to keep your data for a few years, this could really screw you up.
A sysadmin should never cross his fingers in the hope commands will work. Makes for a lot of mistakes while typing.
Please use plain text.
Occasional Visitor
Paul_487
Posts: 3
Registered: ‎10-22-2004
Message 5 of 6 (34 Views)

Re: Problem With SDLT 320 Drive Reading DLT4 Tapes

We decided to migrate all DLT 4 data onto SDLT tapes so we don't have to bother with this issue. It's too bad the HP sales person did not make Cameron's point clear to us when we asked about backward commpatibilty.

But in any case, thank you all for the responses to my question.

~Paul
Please use plain text.
Occasional Visitor
Paul_487
Posts: 3
Registered: ‎10-22-2004
Message 6 of 6 (34 Views)

Re: Problem With SDLT 320 Drive Reading DLT4 Tapes

Thanks again.
Please use plain text.
The opinions expressed above are the personal opinions of the authors, not of HP. By using this site, you accept the Terms of Use and Rules of Participation