ADSM-L

Re: 3592 Tape Compression

2005-11-28 07:16:02
Subject: Re: 3592 Tape Compression
From: Richard Sims <rbs AT BU DOT EDU>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Mon, 28 Nov 2005 07:15:12 -0500
On Nov 28, 2005, at 6:28 AM, Volker Maibaum wrote:

Hello,

We have a TSM Server 5.3.2.1 on z/Linux with a 3494 Library and 3592
Tape drives.

In the 3592 device class I have used the format=DRIVE option (see
below). How can I find out if the data on the volumes is written with
drive compression?

To augment Stef's response...
I'm not aware of a way to inspect the tapes themselves, but you can
ask the drives what they are doing: In AIX, the 'lsattr -EHl rmt_' or
'mt -f /dev/rmt_ status' commands will show whether TSM has enabled
compression in them, as in response:

  attribute      value
description                                user_settable
  compress       yes                Use Hardware Compression on
Tape           True

The average capacity of my volumes is 430GB (> native 300GB). Now I'm
not sure if this is due to client compression or due to drive
compression.

I'm getting about the same, with Format 3592C.

...

   Richard Sims   http://people.bu.edu/rbs

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