ADSM-L

Re: Size of tapes in TSM

2001-09-30 07:44:28
Subject: Re: Size of tapes in TSM
From: Zlatko Krastev/ACIT <acit AT ATTGLOBAL DOT NET>
Date: Sun, 30 Sep 2001 14:42:00 +0300
All this is normal. It is done unintentionally by yourself and the one who
can change it is again you. The explanation:
You did not entered ESTCAP parameter defining device class and TSM assumed
3590E-C. According to TSM help and docs it is 20GB. Use UPD DEV 3590DEV
ESTCAP=40G (or ESTCAP=80G). You can set it to whatever you like but this
may look sometimes strange.
Look at the example (same data on both volumes):

tsm: PUMBA.ACIT.BG>q dev 8mm

Device       Device        Storage    Device       Format     Est/Max Mount
Class        Access           Pool    Type                   Capacity Limit
Name         Strategy        Count                               (MB)
---------    ----------    -------    ---------    ------    --------
------
------
8MM          Sequential          2    8MM          8500C     10,240.0
8MM          Sequential          2    8MM          8500C     10,240.0
DRIVES

tsm: PUMBA.ACIT.BG>q vol

Volume Name               Storage      Device      Estimated    Pct Volume
                          Pool Name    Class Name   Capacity   Util Status
                                                        (MB)
------------------------  -----------  ----------  ---------  -----
--------
--------
DAT000                    8MMPOOL      8MM          10,240.0    0.2 Filling
DAT000                    8MMPOOL      8MM          10,240.0    0.2 Filling

tsm: PUMBA.ACIT.BG>upd dev 8mm estcap=10M
ANR2205I Device class 8MM updated.

tsm: PUMBA.ACIT.BG>q dev 8mm

Device       Device        Storage    Device       Format     Est/Max Mount
Class        Access           Pool    Type                   Capacity Limit
Name         Strategy        Count                               (MB)
---------    ----------    -------    ---------    ------    --------
------
------
8MM          Sequential          2    8MM          8500C         10.0
8MM          Sequential          2    8MM          8500C         10.0
DRIVES

tsm: PUMBA.ACIT.BG>q vol

Volume Name               Storage      Device      Estimated    Pct Volume
                          Pool Name    Class Name   Capacity   Util Status
                                                        (MB)
------------------------  -----------  ----------  ---------  -----
--------
--------
DAT001                    8MMPOOL      8MM              16.4  100.0 Filling
DAT001                    8MMPOOL      8MM              16.4  100.0 Filling


All this is because until tape end is reached all this is an estimate. If
tape in a devclass with estcap=100G fills up to say 77GB it would jump "Pct
Util" from 76.9% to 100%. Same data on a tape in a devclass with estcap=50G
will reach 100% at 50GB and will stay "Pct Util"=100% and "Volume
Status"=Filling until tape end is reached (at 77GB). After that point when
versions expire they create "data holes" on the volume and "Pct Util"
slowly drops down (what in fact happened to your volumes C00031, C00035,
C00057, C00061). When it reaches utilization (100% - REClaim) reclamation
takes place.


Zlatko Krastev
IT Consultant





Michael Bartl <michael.bartl AT CW DOT COM> on 28.09.2001 16:40:19
Please respond to michael.bartl AT de.cw DOT com
To:     ADSM-L AT VM.MARIST DOT EDU
cc:

Subject:        Size of tapes in TSM

Hi Tape Gurus,
on our TSM servers we use a 3494 tape library with Magstart 3590 E1A
drives.
These drives should support a tape size of 20 GB (+compression) on "blue
tapes"
and 40 GB (+compression) on "green tapes". The tapes in our library are
green...

Now in TSM when I do a "q vol" I get results like
          Storage        Device         Estimated       Pct      Volume
          Pool Name      Class Name      Capacity      Util      Status
------    ----------     ----------     ---------     -----     --------
C00011    BACKUPTAPE     3590DEV         20,000.0       0.2     Filling
C00011    BACKUPTAPE     3590DEV         20,000.0       0.2     Filling
C00021    BACKUPTAPE     3590DEV         20,000.0      48.7     Filling
C00031    BACKUPTAPE     3590DEV         49,338.6      59.0       Full
C00035    BACKUPTAPE     3590DEV         43,812.0      73.8       Full
C00057    BACKUPTAPE     3590DEV         54,338.6      75.8       Full
C00061    BACKUPTAPE     3590DEV         52,209.3      84.4       Full

and "q dev 3590DEV"
Device        Device         Storage     Device        Format     Est/Max
Mount
Class         Access            Pool     Type Capacity      Limit
Name          Strategy         Count                                 (MB)
---------     ----------     -------     ---------     ------    --------
------
------
3590DEV       Sequential           2     3590          DRIVE         2
3590DEV       Sequential           2     3590          DRIVE         2

We usually don't use client compression, so I'd expect about 60 to 80 GB
to fit onto the tapes.
Does anybody have an idea why TSM (4.1.4.0 on Solaris) estimates just 20
GB for the 40 GB tapes?

Thanks for any hints,
best regards,
Michael
--
Michael Bartl                               mailto:michael.bartl AT cw DOT com
Michael Bartl                               mailto:michael.bartl AT cw DOT com
System Administrator Backup                 Tel: +49-89-92699-806
Office of Technology, IT Germany/Austria    Fax: +49-89-92699-302
Cable & Wireless Deutschland GmbH., Munich  http://www.cw.com/de
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