HP XP P9500 Storage - Manual (Page 114)

7. In the Confirm window, click Apply to register the setting in the task.
If the Go to tasks window for status check box is selected, the Tasks window appears.
Working with pools
About pools
Thin Provisioning requires the use of pools. A pool consists of more than one pool-VOL. A storage
system supports up to 128 pools, each of which can contain up to 1024 pool-VOLs and 63,232
THP V-VOLs per pool. The pool for Thin Provisioning or Snapshot cannot be used in conjunction
with other pools.
Snapshot also uses pools. The 128-pool maximum per storage system applies to the total number
of both Snapshot pools, and Thin Provisioning pools, and Smart Tiers pools. The pool for Thin
Provisioning or Snapshot or Smart Tiers cannot be used in conjunction with other pools. For more
information, see the HP P9000 Snapshot User Guide.
A pool number must be assigned to a pool. Multiple THP V-VOLs can be related to one pool.
The total pool capacity combines the capacity of all the registered Thin Provisioning pool-VOLs
assigned to the pool. Pool capacity is calculated using the following formulas:
•
capacity of the pool (MB) = total number of pages × 42 - (4116 + 336)
•
total number of pages = Σ(floor(floor(pool-VOL number of blocks ч 512) ч
168)) for each pool-VOL
where
•
floor( ) means to truncate the part of the formula within the parentheses after the decimal point.
About pool-VOLs
Pool-VOLs are grouped together to create a pool. When a new pool is created, the available
pool-VOLs are selected in the Select Pool VOLs window and added to the Selected Pool Volumes
table. Every pool must have a pool-VOL with System Area.
During initial creation of a pool, designate a pool-VOL as the pool-VOL with System Area, select
the pool-VOL, and click Change Top Pool VOL in the selected pool volumes table.
When adding a volume to the pool for which Multi-Tier Pool is enabled, note the following:
•
Up to three different drives types/RPM are allowed between all the pool-VOLs to be added.
•
Volumes to be added to the same pool must have the same RAID level across all the same
drive type/RPM pool-VOLs.
For example, you cannot add a volume whose drive type/RPM is SAS/15k and whose RAID
level is 5 (3D+1P) when a volume whose drive type/RPM is also SAS/15k but whose RAID
level is 5 (7D+1P) is already in the pool
•
Up to three values are allowed for Drive Type/RPM for the volume.
If you increase the pool capacity by adding a pool-VOL, a portion of the existing data in the pool
automatically migrates from an older pool-VOL to the newly added pool-VOL, balancing the usage
levels of all the pool-VOLs. If you do not want to automate balancing of the usage levels of
pool-VOLs, call the HP Technical Support for assistance.
Thin Provisioning does not automatically balance the usage levels among pool-VOLs if the cache
memory is not redundant or if the pool usage reaches up to the threshold.
The pool-VOLs contained in a pool can be added or deleted. Removing a pool-VOL does not delete
the pool or any related THP V-VOLs. You must delete all THP V-VOLs related to the pool before the
pool can be deleted. When the pool is deleted, all data in the pool is also deleted.
114 Configuring thin provisioning