Bernd,

Think about this first!

Removing the client compression will
 1) probably make this client's backups run faster as there will be no cpu limitation 
to the process.
 2) send data across the network uncompressed instead of compressed - this could have 
capacity implications
 3) fill your disk storage pool with uncompressed rather than compressed data. This 
may trigger migrations at unusual times.
 4) allow your tape drives to do the compression as desired.

My thinking is that compression at the client is in general a better idea than 
compression at the drives - always do both though, because compression at the drives 
costs nothing.  In those few cases where it isn't a good idea the later clients have 
exclude.compression directives available for problem files.

Regards

Steve Harris
AIX and TSM Admin
Queensland Health, Brisbane Australia



>>> [EMAIL PROTECTED] 09/09/2003 0:45:47 >>>
Bill,

thanks for your answer.

 >>If this is a copy storage pool for your primary server, what are the
 >>server to server device class settings?

I just did a on the TSM server

tsm: TSM2>q node type=server f=d

and found that compression is enabled for the client:

                    Compression: Client

I think, that might be the reason for the problem. I'll change it
tomorrow and see what happens.

Bernd


Bill Smoldt wrote:
> Bernd,
>
> The device class is the only place within TSM where you can affect
> compression.
>
> It's been a long time since I've used a drive without compression, but I
> believe you'd see a more consistent capacity with compression turned off.
> If you were consistently getting 37G, I could believe that compression was
> turned off, but you have tapes with more and less than that.
>
> If this is a copy storage pool for your primary server, what are the server
> to server device class settings?
>
> A "query content <volume_number> f=d" will show you the stored size of a
> file on tape.
>
> Bill Smoldt
> STORServer, Inc.
>
> -----Original Message-----
> From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED] Behalf Of
> Bernd Schemmer
> Sent: Saturday, September 06, 2003 9:53 AM
> To: [EMAIL PROTECTED] 
> Subject: 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
>
> --
>
>

--
----------------------------------------------------------------------------------------
Bernd Schemmer, Stalburgstr. 14, 60318 Frankfurt, Germany
email: [EMAIL PROTECTED] 
Phone/Fax: +49 - 69 /  95520301
mobil: +49 - 179 / 4647978


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