HP XP P9500 Storage - Manual (Page 75)

Pool requirements
A pool is a set of volumes reserved for storing Thin Provisioning write data.
Requirements Items
Calculate pool capacity using the following formula: Pool capacity
The capacity of the pool (MB) = Total number of pages × 42 - 4200 .
4200 in the formula is the management area size of the pool-VOL with System Area.
Total Number of pages =
Σ(floor(floor(pool-VOL number of blocks ч
512) ч 168)) for each pool-VOL.
floor( ): Truncates the value calculated from the formula in parentheses after the decimal point.
However, the upper limit of total capacity of all pools is 5.0 PB if the shared memory is installed.
From 1 to 1,024 volumes (per pool). Max number of
pool-VOLs
A volume can be registered as a pool-VOL to one pool only.
Up to a total of 128 pools per storage system. This is the total number of Thin Provisioning
(including Smart Tiers) pools, Fast Snap, and Snapshot pools. Maximum number of
pools
Pool IDs (0 to 127) are assigned as pool identifiers.
You can increase pool capacity dynamically. Increasing capacity by one or more parity groups
is recommended by adding pool-VOLs. Increasing capacity
You can reduce pool capacity by removing pool-VOLs. Reducing capacity
You can delete pools that are not associated with any THP V-VOLs. Deleting
You can set the percentage of the total relative THP-VOL capacity that can be created to prevent
the THP V-VOL from becoming unwritable when the pool is full. Subscription limit
When the subscription limit is, for example, set to 100%, the formula of THP-VOL capacity that
can be created is calculated as follows.
The total THP-VOL capacity <= Pool capacity × 100% .
Reaching the subscription limit will restrict the ability to shrink the pool, create a new THP V-VOL,
or expand a THP V-VOL.
Thresholds •
Warning Threshold: You can set the value between 1% and 100%, in 1% increments. The
default is 70%.
•
Depletion Threshold: You can set the value between the warning threshold and 100%, in
1% increments. The default is 80%.
Pool usage over either threshold will cause a warning to be issued via a SIM reported to Remote
Web Console.
42 MB Data allocation unit
The 42-MB page corresponds to a 42-MB continuous area of the THP V-VOL. Pages are allocated
for the pool only when data has been written to the area of the THP V-VOL.
Defined based on the media type (see Drive type for a Smart Tiers tier, below). Maximum 3
tiers. Tier
(Smart Tiers)
4.0 PB (Total capacity of the tiers must be within 4.0 PB. The shared memory must be installed.) Maximum capacity
of each tier
(Smart Tiers)
Thin provisioning requirements 75