tape compression

[vu pham]

C M Reinehr wrote:
[...]
>> Do I have to run any extra command to force the tape drive to use
>> compression mode ? I already tried "mt -f /dev/st0 compression 1" but it
>> does not help.
>>

> What Bill says is very true, but here are some utilities that can be very 
> helpful in figuring out what's going on. The tapeinfo command which comes in 
> the mtx package can tell you explicitly if your hardware data compression is 
> turned on or off. Check out, also, the scsitape command from the same 
> package. Finally, there is the sg3_utils package which contains a number of 
> useful SCSI utilities.
> 
> Here's what the output of the tapeinfo command looks like on my system with a 
> Tandberg LTO2 tapedrive:
> 
[...]
> By the way, the command that I use to turn compression on & off is: 
> mt -f /dev/nst0 defcompression 1
> 
> Another thing is that with some tape drives (or so I've read) is that the 
> compression & defcompression commands do not work. You have to set the 
> density code.

CM, thanks for your advice.
I just installed the package mtx, but it complains that there is no sg 
devices on my server. This server is a RH9. Can I make it see the tape 
drive as sg device ?

Thanks,

Vu