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You can convert your data from non-collocating to collocating. There are a
number of ways to do it; I don't recommend export/import.
Assume that you have 100 tapes now and 100 nodes. Update the storage pool
to be collocating and start issuing 'move data volume=xxxxxx' commands.
The worst case is that each tape has data from every node. ADSM will mount
a new tape and move data from node 1 onto it, then another new tape for
node 2, etc. In this worst case you will need to mount 100 collcated tapes
for each input tape, or 10,000 mounts altogether.
You can cut this down alot. Start collocating now and leave the old tapes
alone. Let them age. When there isn't so much data on them, do the moves.
Better still, move the input tapes to the diskpool, perhaps 10 at a time,
then migrate the diskpool. Now the worst case is 1,000 output tape mounts.
If you can add some extra space to the diskpool, you can integrate the
conversion process with your normal day to day operations.
I converted 1,000+ tapes from non-collocating to collocating by moving them
to disk first, 40 tapes at a crack, mostly during slack periods on the
weekends.
A trick to improve operations using collcating tapes is to not migrate to
0. Since the largest nodes are moved first, you get the largest amount of
diskspace freed up by the first few nodes which are migrated. Let the
smallest nodes stay on disk until they are large. This saves tape mounts.
Bill Colwell
The Charles Stark Draper Laboratory
Cambridge Ma.
_________________________Reply Header_________________________
Author: ADSM-L AT vm.marist DOT edu
Subject: moving from NoCollocation to Collocation
01-13-1997 08:58 AM
Date: Mon, 13 Jan 1997 08:58:32 -0500
From: Matthias Brasch <100673.411 AT compuserve DOT com>
Subject: moving from NoCollocation to Collocation
To: Multiple recipients of list ADSM-L <ADSM-L AT vm.marist DOT edu>
Hi to all ADSM'ers,
when I started working with ADSM I defined the destination storage pool
(tape) to be an pool without
collocation.
Meanwhile I've seen that a restore of many files requires
many tapes to be mounted because only a part of the tape
consists info of the node I want files to be restored for.
So my question is :
Is it possible to move data from no-collocation to collocation ?
Could this be done by export/import node ?
Anyone any idea ?
Best regards,
Matthias Brasch, HEW-Hamburg Germany, M_Brasch AT compuserve DOT com
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