HP XP P9500 Storage - Manual (Page 19)

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A Remote Web Console client computer.
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A minimum of 1 pair of FICON CHAs.
Shared memory requirements
If configuring thin provisioning, Thin Provisioning Z requires dedicated shared memory for the
V-VOL management area.
The V-VOL management area, which is automatically created when shared memory is added, is
an area used to store information for associating pool-VOLs and THP V-VOLs.
If Thin Provisioning Z is used, at least 16 GB of shared memory consisting of two sections is
required. The memory capacity allocated to each part is as follows:
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Basic part: 8 GB
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Thin Provisioning Z: 8 GB
If Thin Provisioning Z and Smart Tiers Z are used, the capacity that can be created depends on
the amount of shared memory installed. If you use a pool with a capacity greater than 1.0 PB, the
optional shared memory must be installed. If the THP/Smart Extension is uninstalled, all pools for
Thin Provisioning Z and Smart Tiers Z have to be deleted before the shared memory is uninstalled.
The required shared memory is installed by your HP representative.
About pool volumes
Pool volumes are logical volumes (LDEVs) defined in a parity group. Pool volumes are assigned to
a specific THP pool to allow the definition of THP V-VOLs and provide physical space defined for
allocated data. There must always be a minimum of one LDEV assigned to a parity group. The
capacity of the parity group may result in the need for multiple pool volumes to be defined for the
parity group. Depending on the size of the LDEVs defined as pool volumes, a V-VOL or a collection
of V-VOLs may require more than a single pool volume when the V-VOL allocated size reaches the
defined maximum. This topic describes how to calculate the number of pool volumes required for
a pool. In the Remote Web Console, LDEVs used as Pool volumes are referred to as Cache
Management Devices.
Calculating the number of pool volumes required by a THP V-VOL
The number of pool volumes that a THP V-VOL requires depends on the capacity of the V-VOL
(capacity of the user area) and the maximum capacity of pool volumes. The maximum capacity of
pool volumes depends on the location of the pool (internal volume or external volume) associated
with V-VOL. The following table explains the relationship between the pool attribute and the
maximum capacity of a pool volume. It is possible to define pool volumes smaller than the maximum
size.
Maximum capacity of pool volumes
Maximum capacity
(in cylinders)
Maximum capacity
(in blocks)
Maximum capacity
(in MB)
Pool attribute
837,760 1,457,702,400 711,768.75 Internal volume
(695.08 GB)
1,117,760 1,944,902,400 949,659.37 External volume
(927.40 GB)
Use the following formula to calculate the number of pool volumes that a THP V-VOL requires. In
this formula, the user-specified capacity is the user area capacity of a V-VOL.
About pool volumes 19