ADSM-L

Re: Performance point of view

2001-02-19 13:13:54
Subject: Re: Performance point of view
From: David Longo <David.Longo AT HEALTH-FIRST DOT ORG>
Date: Mon, 19 Feb 2001 13:14:07 -0500
When going to sequential drives, a single migration process will sequentially 
store files on ONE volume until it is filled (or a I/O error occurs on tape) 
and then proceed to the next tape.  One large (or not so large) file can and 
will span multiple volumes if EOT is reached on a tape and the file has not 
been completely copied/migrated.  I have seen this happen many times  (TSM 
server 3.7.4.0 is out current).

Thus a file, regardless of size is attempted to be put on as few tapes as 
possible.  I believe this is the same for collocation, but don't use 
collocation here.



David B. Longo
System Administrator
Health First, Inc.
3300 Fiske Blvd.
Rockledge, FL 32955-4305
PH      321.434.5536
Pager  321.634.8230
Fax:    321.434.5525
david.longo AT health-first DOT org


>>> KlattM AT EUROPE.STORTEK DOT COM 02/19/01 12:59PM >>>
Hi all,

I would like to get some help/infos/ideas for better understanding the
performance point of view.

If some clients are backed up into a disk storage pool, the data (files)
from this storage pool will be migrated into the next storage pool (type
sequential for example) if watermarks are reached. During this migration the
files are stored at the end of the chain "storage pool" -- "device class" --
"library" -- "drives" to drives, to all available drives I assume and  
"library" -- "drives" to drives, to all available drives I assume and  isn't
collocation  enabled all files are distibuted over the volumes, but no
single file is spread out over the volumes. This means to me,  that one huge
file would be stored to just one drive, even if  many drives available,
correct ?

As far as I know about TSM it is different in the TDP for SAP, there I can
stream to different tapes, but what about TDP for Oracle and how can I
manage to get a huge file saved as fast as possible?

many thanks for your help


regards
Michael



"MMS <health-first.org>" made the following
 annotations on 02/19/01 13:19:20
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