How to check if TSM is using hw compression?

Hello,

Using TSM 5.1.6.2 on Solaris 8 with a Sun L20 Tape Library (using DLT8000
drives) how can I check if TSM uses the hardware compression of the drives?

We use the TSM driver to access the drives (so there's no special driver
for using the drives in compression mode). The only way to configure hw
compression in TSM I found is to configure the approbate drive format in
the device class (DLT35C or DLT40C) (Is there another way to configure
the hardware compression?) I did this but TSM still only writes about
37.000 MB on 35/70 GB DLT IV Tape. This is independent from the kind of
data written. We use the server only for a Copy Storage Pool of our
primary server. The data to backup is mostly Oracle DBs, Filesystem
backups, Domino Data backups, etc.

Some TSM output:

tsm: TSM2>q volume

Volume Name               Storage      Device      Estimated    Pct   Volume
                          Pool Name    Class Name   Capacity   Util Status
                                                        (MB)
------------------------  -----------  ----------  ---------  ----- --------
/tsm/01/archive/archive-  ARCHIVEPOOL  DISK         20,000.0    0.0  On-Line
 pool_vol001.dsm
/tsm/01/backup/backuppo-  BACKUPPOOL   DISK         20,000.0    0.0  On-Line
 ol_vol001.dsm
ARZ00016                  LIBRARYL20   DEV1         38,621.3   94.1    Full
ARZ0003                   LIBRARYL20   DEV1         35,305.2  100.0    Full
ARZ0004                   LIBRARYL20   DEV1         71,680.0   19.4  Filling
ARZ0005                   LIBRARYL20   DEV1         31,060.1  100.0    Full
ARZ0006                   LIBRARYL20   DEV1         71,680.0   26.7  Filling
ARZ0011                   LIBRARYL20   DEV1         45,654.5  100.0    Full
ARZ0013                   LIBRARYL20   DEV1         37,968.0  100.0    Full
ARZ0014                   LIBRARYL20   DEV1         37,125.2  100.0    Full
ARZ0015                   LIBRARYL20   DEV1         33,276.5  100.0    Full
ARZ0016                   LIBRARYL20   DEV1         40,359.1  100.0    Full
ARZ0017                   LIBRARYL20   DEV1         38,636.0   99.7    Full
ARZ0018                   LIBRARYL20   DEV1         37,670.3  100.0    Full
ARZ0019                   LIBRARYL20   DEV1         37,165.9  100.0    Full
ARZ0021                   LIBRARYL20   DEV1         33,153.4  100.0    Full

tsm: TSM2>q devclass dev1 f=d

             Device Class Name: DEV1
        Device Access Strategy: Sequential
            Storage Pool Count: 1
                   Device Type: DLT
                        Format: DLT35C
         Est/Max Capacity (MB): 71,680.0
                   Mount Limit: 2
              Mount Wait (min): 60
         Mount Retention (min): 60
                  Label Prefix: ADSM
                       Library: L20
                     Directory:
                   Server Name:
                  Retry Period:
                Retry Interval:
                        Shared:
Last Update by (administrator): ADMIN
         Last Update Date/Time: 09/04/03   12:13:27


Looking at this output I think, that TSM does not use the hardware
compression at all. Or am I wrong?


TIA

Bernd

--