mt -f <st device> datcompression 0

That should work but it will likely come back on after a restart though.

--On May 2, 2006 10:17:48 AM -0400 Guy Dallaire <clepeterd AT gmail DOT com> 
wrote:

Hi,

Recently added an Overland LoaderXpress LTO 2 tape library to my setup.
Inside the loader is an OEM HP Ultrium tape drive. My tape server is a
centos 4.2 box (RHEL 4 clone)

I'm using software compression with amanda 2.4.5p1 already.

Problem is, the tape drive in the library always seems to have hardware
compression ON. There is no way on the library operator panel to force
the compression OFF.

I've heard that LTO2 drives can easily cope with already compressed data
(and do not try to re compress it). Is this true ? Otherwise, I fear that
trying to compress already compressed data might actually use more tape
space and reduce throughput.

I've searched the amanda wiki and di not find anything.

Has anyone devised a way to force hw compression off on a similar setup ?

Thanks

--
"Genius might be described as a supreme capacity for getting its possessors
into trouble of all kinds."
-- Samuel Butler