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
>>> Bernd.Schemmer AT GMX DOT DE 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:ADSM-L AT VM.MARIST DOT EDU]On Behalf Of
> Bernd Schemmer
> Sent: Saturday, September 06, 2003 9:53 AM
> To: ADSM-L AT VM.MARIST DOT EDU
> 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: Bernd.Schemmer AT gmx DOT de
Phone/Fax: +49 - 69 / 95520301
mobil: +49 - 179 / 4647978
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