HP XP Racks - Manual (Page 109)

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Reclaiming zero pages in a page release request issued by the host with the Write Same
command, for example.
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Performing tier relocations several times
If you expand the pool capacity, Thin Provisioning moves data to the added space on a per-page
basis. When the data is moved, the usage rate among parity groups of the pool-VOLs is rebalanced.
Host I/O performance may decrease when data is moved. If you you do not want to have the
usage level of parity groups automatically balanced, call the HP Technical Support.
You can see the rebalancing progress of the usage level among parity groups in the View Pool
Management Status window (see
“View Pool Management Status window” (page 375) ). Thin
Provisioning automatically stops balancing the usage levels among parity groups if the cache
memory is not redundant or the pool usage rate reaches up to the threshold.
Execution mode settings and tiering policy
The follow depicts how tier relocation is performed after changing the tiering policy setting while
Auto execution mode is used.
The following depicts two cases of how tier relocation is performed after changing the tiering policy
setting while Manual execution mode is used.
Smart Tiers 109