ADSM-L

Migration from DISKPOOL with maxpr=2 query

1998-12-18 09:14:48
Subject: Migration from DISKPOOL with maxpr=2 query
From: Thomas Denier <Thomas.Denier AT MAIL.TJU DOT EDU>
Date: Fri, 18 Dec 1998 09:14:48 -0500
> Dear all,
Nolan Rogers wrote:
> We have recently set up our ADSM server so that the nightly incrementals
> backup to a large disk pool(BACKUPPOOL) which is then copied to our
> DR_TAPEPOOL after the incrementals complete.
> At the moment, BACKUPPOOL is filling up during the night, forcing some
> automatic migration to the internal tapepool to occur.
> What I do not understand is why the BACKUPPOOL is showing only 40.5%
> (Pct Migr) left to migrate in the morning, surely this should be 80%
> (hi=90 lo=80) in accordance with the parameters shown below. Looking
> Does the fact that we are using two migration processes (migpr=2) have
> any effect on this?

Do you have two large clients that account for half of the disk storage pool
between them? Once ADSM starts migrating files for a client, it migrates all
of that client's files, even if doing so takes the amount of data awaiting
migration well below the lower migration threshold. For example, if the two
biggest clients were using 30% and 20% of the disk storage pool when overall
use reached 90%, two migration processes would start, with one migrating files
for the 30% client and the other migrating files for the 20% client. Each
would migrate all of the files for its first client, taking the percent
migratable vaue down to 40%. As each migration process finished migrating
files for its first client it would check the current statistics, note that
the percentage of migratable data was below the low migration threshold, and
terminate.
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