tar + hardware compression

[Voja]

hello
I've read some of documentation about the subject but did not find a good solution for it. The problem is:
Tar puts xxxx-20% (xxxx=DDS2-3-4 capacity, dds4=20-4gb in this case) on the tape and I can't make it to use hardware compression at least. Now, I'm using default values - could block size of 0 be a solution for full capacity (dds4=20gb, for instance)?
why does mt -f /dev/st0 compression 0,1,2 give no result?
Hardware:
Ibm e series x server 235 with seagate dds4 tape.
OS: RH9

 

[ShamanHack]

Voja,

Seagate tape drives have a dip switch that must be on before hardware compression will be used. You may want to check the position of the switches.

Just taking a guess at the model you have (STD2401LW ??) it would be Switch 1. Also Switches 5-8 are changed depending on the operating system you are using. You may want to inspect those as well.

Here's a manual page:

http://www.certance.com/support/kb/tape/howto/dati_cfg_scor40.html

Hope this helps,
Shaman

 

[Voja]

well, the drive is seagate dat 9sp40-000 actually, but you gave me another idea-to look for the dip switch.
Thanks