I have a new set of X23 tapes from Exabyte (now Tandberg) that I want to
make sure I get the most out of with my AMANDA backup system.  The tapes
are rated at 80/160 GB (uncompressed/compressed) for my VXA-2 drive.  A
few questions:

1) compresstion

I read where hardware compression in the tape drive should not be used
with AMANDA.  If you want compression, use the computer software (gzip)
to do this in the AMANDA configuration.  Is this still true ?

2) block size

I have read mixed advice on the blocking size.  It seems that a variable
blocking size (mt setblk 0) is the best, but I have also seen where a
large fixed block size like 32768 is appropriate.  I tried this fixed
block size and it seem to fail my system, so I changed it back to
variable.  What is the advice here ?

3) tape density

The VXA-2 manual and the output from "mt status" indicate that a tape
density parameter of 0x81 is being used by this tape drive.  However,
the output from "mt densities" shows 0x81 as "DLT 15 GB compressed".  I
want the setting that will give me 80GB on the tape.  What would that
be ?

4) stinit.def file

I am using the debian mt-st package.  The drive is presently initialized
with a /etc/stinit.def file shown below.  How should I change this (if
any) ?
        
        manufacturer = "EXABYTE" model = "VXA-2" revision = "2100" {
        scsi2logical=1
        density=0x81
        can-bsr=1
        can-partitions=1
        auto-lock=1
        async-writes=1
        read-ahead=1
        buffering=1
        mode1 blocksize=0 compression=0
        mode2 blocksize=0 compression=1
        mode3 blocksize=32768 compression=0
        mode4 blocksize=32768 compression=1
        }
        

-- 
James D. Freels, Ph.D.
Oak Ridge National Laboratory
freelsjd AT ornl DOT gov