HP DDS4 Native Capacity issues

[Yiannis Mavroukakis]

Hello,

I have the following DAT drive installed on my system
Host: scsi0 Channel: 00 Id: 03 Lun: 00
Vendor: HP Model: C5683A Rev: C305
Type: Sequential-Access ANSI SCSI revision: 03

I am coming up against an odd problem. I am backing up 15Gb of data, which should fit on the drive without compression. However, at around 11Gb, whatever software I may use at the time (and I tried a few) asks me to change tapes as capacity has been reached!
Any idea why this might be happening?

P.S. This thread has been moved from Archival Products to Tape Libraries and Drives - HP Forums Moderator

[CA1064576]

Yiannis:

Be sure than you are using the correct tape for this drive. To use the 20GB /40GB with this drive you mus use the C5718A tape.

Every DAT drive can read the current and two previos generations (DDS4, DDS3 and DDS2) and write the current and a previos generation (DDS4 and DDS3).

If you are using a DDS3 tape(C5708A), may be this just accept 12GB by tape.

[Yiannis Mavroukakis]

I actualy am using the C5718A, fresh sealed tape :)

[meloni]

capacity lost may depend of various factors:
bad tape bad drive
but also caused by overhead, if you compress already compressed data, if you select sw compression on your software and use also the hardware coompression, if your drive is not streaming, communication problems, all these factor can cause capacity lost.

I would suggest to run L&TT, there is the possibility to create a amount of data with a well known compression capability, then you can send these data to your unit and see what happens. what is your backup application?
Do you have any error in your system log related to scsi problems?

[Yiannis Mavroukakis]

Ok I suppose I should clarify.

I am not using compression on the drive, and I have tried with a 15Gb dummy file, only to come up against the same problem.

I tried several different tapes, and the issue is still there. My scsi logs have no errors whatsoever. I tried using BRU, Tapeware and mt (i use linux) to perform the backup, and all have wielded the same results, so I am at somewhat of a loss here.
LTT performed test all come through with no errors.