Automated Media Pools white paper for ESL G3 (QN998-96026, June 2011)

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In Summary
The use of an Automated Media Pool (AMP) within a tape library provides a flexible way to grow and
shrink virtual libraries based upon changes in customer storage demands. It removes the need for
investment and management of dedicated sharing software, while overcoming the inflexibility of
fixed-partition approaches. The AMP feature is available in the HP ESL G3 Tape Library from June 2011.
© Copyright 2011 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice. The only
warranties for HP products and services are set forth in the express warranty statements accompanying such products and services. Nothing herein
should be construed as constituting an additional warranty. HP shall not be liable for technical or editorial errors or omissions contained herein.
Dealing with change
The previous scenario may continue to meet customer
needs for a number of months. However, with IDC
predicting annual data growth by a factor of x45, it
is just a matter of time before the customer’s storage
requirements increase to keep pace with their data.
When more storage is required, the slots in the AMP
can be made available to the customer’s partition,
and subsequently appear as ‘accessible’ to the ISV
application. Unlike traditional partitioning, with the
HP ESL G3 Tape Library this is a simple task that can
be done by assigning magazines of media from the
AMP to a partition using the Library Management
Console (LMC) of the Tape library.
To demonstrate: we might assume that to satisfy
increased backup capacity requirements, Customer A
now requires 48 slots, an increase of 24 tape slots.
A simple slot assignment using the Tape Library LMC
assigns 6 magazines (24 pieces of media) from the
AMP to Partition 1. As a result of the management
command, the tape library software updates its
internal database, allocating 24 more slots of media
from the AMP to Partition 1.
At the end of this procedure, Partition 1 offers 48
slots for Customer A’s backup, while the total amount
of available slots remaining in the AMP drops to 72
slots. This is illustrated in figure 3.
With fixed partitions, the addition and subtraction of
slots would result in a change in the library size, and
ISV applications would need reconfiguration. Often,
the addition of slots in one fixed partition will require
taking slots from another fixed partition. This would
require ISV reconfiguration for both virtual libraries.
With AMP, the additions and subtractions don’t affect
other partitions. This entire procedure is completed
without any physical change to the tape library, or
any reconfiguration of the ISV software. As far as the
software is concerned, the size of Partition 1 hasn’t
changed – it simply has more ‘accessible’ media with
the current configuration.
Note that media slots can also be assigned from
a Partition back to the AMP should customer
requirements ever shrink.
Figure 3: Logical allocation
after media assignment – as
seen by the ISV application
Partition 1 (120 slots) 48 accessible
ISV View
AMP = 96 slots
Partition 2 (120 slots) 24 accessible
QN998-96026