MSL5026 - SDLT220 - Super DLTtape 1 lifespan

[Art Wiens]

Are there specs anywhere as to how long I can expect my tapes to last? We've been using a 2 week rotation for ~1.5 years ( call it ~40-50 passes, usually recording ~150GB /pass /tape ). They're starting to give parity errors. At $100 a piece it seems a bit premature to me. I use both Quantum and Compaq branded tapes ( probably the same manufacturer ).

Thanks in advance,
Art

[David Ruska]

The SDLT tapes are rated for 1,000,000 passes, which sounds like a lot, but you need to understand the tape format a bit to know how many "passes" are used in each tape use. The SDLT220 had 448 tracks layed out in a serpentine fashion. If you wrote the full tape each time, you technically could do 17,850 uses of the tape to get to 1,000,000 passes. In reality, there are other factors (like not streaming) and additional passes at the beginning of the tape on each load/unload (i.e. calibration and directory read and updates).

The bottom line however is you should get at least a few hundred backup uses of the tape, which is much less than the 40-50 you mentioned.

Can you install HP Library & Tape Tools (www.hp.com/support/tapetools), and generate a support ticket for the library (which includes the drives)? I'd like to review the drive logs to see the types of errors you are getting. You can email the support ticket to ltt_team@hp.com.

[Art Wiens]

Thanks, but this library is used on VMS 7.2-2 systems and according to the info on the link:

"Operating systems currently supported include all flavors of Windows, HP-UX v10.20 and HP-UX v11.x, NetWare v5.01 and v6.0 above, Tru64, and Linux Red Hat 7.2, 7.3 and 8.0."

But thanks for the other numbers. How about the drives themselves? We've had one unit (the least used of the 4 drives in our two libraries) that we've had to replace 3 times already.

[David Ruska]

Art,

You are correct - LTT is not yet supported on VMS (a port is being worked on, any it may be available in the summer).

Can you send your email address to ltt_team@hp.com, and we can discuss other ways to troubleshoot the cause of errors?