Re: tape speeds, TSM and pase

[rob@xxxxxxxxx]

So, has anyone out there have some time trials of save times using various 
tape drives on Linux, guested or dedicated?

Rob Berendt
-- 
Group Dekko Services, LLC
Dept 01.073
PO Box 2000
Dock 108
6928N 400E
Kendallville, IN 46755
http://www.dekko.com





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tape speeds, TSM and pase






3582 runs 131GB/hour native
3582 runs 33GB/hour TSM underneath PASE
PMR with IBM says that it is because PASE API's to talk to tape drive are 
limited to size chunks and really kills the speed.  Repeat, it's a PASE 
issue and not a TSM issue.
3581-H17 runs 32GB/hour TSM underneath PASE.
Therefore the better hardware of the 3582 gets you little to no speed 
improvement when using TSM underneath PASE.  Just higher tape volume.
This was NOT the normal grandfather... stuff of moving stuff from disk to 
tape that TSM does.  This was a TSM backup of the entire disk pool to the 
tape pool to move it offsite.  Therefore that grandfather logic was not 
part of the equation.

TSM command used:
backup stg backuppool lto_3581_week1

IBM says it's a limitation of PASE and have no intention of 'beefing' up 
the api's to pipe data to the tape drive any faster.  Workaround:  Dump 
OS/400 and try a Linux or Unix partition.

Will running TSM on a Linux partition on my i5 get me any faster response 
from LTO2 and/or LTO3 tape drives than running TSM underneath PASE?

TSM 5.2.2
OS/400=V5R3M0

Rob Berendt
-- 
Group Dekko Services, LLC
Dept 01.073
PO Box 2000
Dock 108
6928N 400E
Kendallville, IN 46755
http://www.dekko.com

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