SureStore DAT8 only backing up 3GB

[kevin warner_2]

Using a SureStore DAT8 and various brands of DDS2 120 4/8GB tapes. Using NT4 Server SP6A, and native NT backup program. According to the drive properties of the two drives we're backing up, it looks like we're only trying to back up around 3GB of data. If we exceed the 3GB threshold, it asks for a second tape. This occurs with or without hardware compression enabled. So two questions: 1) Why is it only backing up 3GB using various brands of tapes (that we verified were supposed to be 4GB tapes)?, and 2) Why does the amount that we can back up NOT change whether HW compression is enabled or not?
Any advice or information would be greatly appreciated.

[BR642007 · Accepted solution]

It might be that your data is already compressed, turning hardware compression on doesn??t improve anything.
NT Backup is not a very fast program, it might be too slow to keep your DAT8 in streaming mode, resulting in blank spaces on your tape.
A very good and easy way to test your configuration in installing and running HP Library & Tape Tools.
It can do a compression test, tell you if your drive is in streaming mode and much more data about the performance of your tape drive.
You can download it from: http://www.hp.com/cposupport/information_storage/software/ltt_27_eng.exe.html

You also might want to check the output of the performance assessment tool : http://www.hp.com/cposupport/information_storage/software/ltt_27_eng.exe.html

Hope this helps.

Marco.