HP XP RAID Manager Software - Manual (Page 18)

The following table shows the pool capacity for shared memory and the P-VOL capacity that you
can create.
Pool capacity (GB) Shared
memory
30,720 20,480 14,336 12,288 10,240 8,192 6,144 4,096 2,048
- - - - - - - 11 (TB) 26 (TB) SS
12 88 (TB) 133 (TB) 148 (TB) 163 (TB) 179 (TB) 194 (TB) 209 (TB) 224 (TB) SS Extension
1
(TB)
The total capacity of pool-VOLs registered in a pool is the capacity of that pool. The capacity of
the pool you want to create depends on the shared memory extension status.
The following graph roughly shows the relationship between the allowable pool capacity and the
P-VOL capacity depending on the shared memory extension status.
Calculate the capacity of the pool management block
The capacity of the pool management block is the total capacity of shared memory used by the
pool-VOL.
Use the following formula to calculate the capacity:
Capacity (bytes) of shared memory used by the pool-VOL = ceil (floor (pool-VOL capacity (KB)/256 (KB)) X 32/8,640)
X 8,736 + ceil (ceil (floor (pool-VOL capacity (KB)/256 (KB)) X 32/8,640)/2,048) X 8,736 + ceil (ceil (ceil
(P-VOL capacity (KB)/256 (KB)) X 32/8,640)/2,048)/1,024) X 8,736
Copy capacity and creating pools
Estimate the copy capacity (the capacity of SS data to be copied to the pool) and then set the pool
capacity large enough to accommodate the copy capacity. If the copy capacity varies according
to time, use the maximum copy capacity in your calculation. Creating a pool when the pool capacity
is insufficient can suspend the SS pairs (“PSUE” status).
Pool capacity and copying SS data
Copying SS data to the pool consumes the pool capacity in units of 256 KB. You must allow for
this amount of pool capacity even in situations where less than that amount is consumed.
Capacity of pool association information
The capacity of the pool association information is the total capacity of shared memory used by
the P-VOL.
18 Business Copy/Snapshot planning and design