After you determine the necessary number of differential and pair tables, determine whether
the planned number of pairs can be created.
The number of differential and pair tables for a pair depends on the volume capacity.

Calculate how many differential tables are required for the planned number of pairs:
numberofdifferentialtablesperpair × plannednumberofpairs

Calculate how many pair tables are required for the planned number of pairs:
numberofpairtablesperpair × plannednumberofpairs

Verify that the storage system has enough differential tables and pair tables available.
 The number of differential tables calculated in step 1 must not exceed the number of available differential tables
 The number of pair tables calculated in step 2 must not exceed the number of available pair tables
Note:
 When creating ShadowImage pairs with multiple
volumes that have different capacities, apply the total numbers of differential
tables calculated for each volume.
 When creating ShadowImage pairs with multiple
volumes that have different capacities, apply the total numbers of pair tables
calculated for each volume.
 The number of available differential tables and pair tables depends
on the amount of installed shared memory.
Example
if you plan to create 20 pairs in a storage system that has 57,600 differential tables, use the following calculation:
577 × 20 = 11,570, which is ≤ 57,600
If the capacity of the volume is 3,019,898,880 KB, you will need 577 differential tables and 17 pair tables.
Apply these numbers to the following formula:
577 × 20 = 11,570 ≤ 57,600
and
17 × 20 = 340 ≤ 8,192
Therefore, you can create 20 pairs.