HP XP Racks - Manual (Page 22)

Table 15 The number of differential tables, pair tables and system volumes per additional shared
memory type
the number of system
volumes the number of pair
tables the number of
differential tables Additional shared memory for Auto LUN
16,384 8,192 57,600 Base (no additional shared memory)
65,536 32,768 419,200 Extension
The emulation type and capacity of each volume to be migrated.
The number of differential tables and pair tables needed to migrate one volume differs based on
the emulation type and size of the volume. For the number of differential tables and pair tables
needed for migrating a mainframe volume, see
“Calculating the required amount of differential
tables for a mainframe volume” (page 19) . For the number of differential tables needed for migrating
an open-system volume, see “Calculating the required amount of differential tables for an
open-system volume” (page 20) .
Estimating the number of concurrent migration plans
The following conditional expression can be used to estimate the maximum number of migration
plans that can be executed concurrently:
Σ(α) ≤ (β) and Σ(γ) ≤ (δ)
The variables are explained below:
•
Σ (α): total number of differential tables needed for migrating all volumes.
•
(β): total number of differential tables available in the storage system.
•
Σ (γ): total number of pair tables needed for migrating all volumes.
•
(δ): total number of pair tables available in the storage system.
As calculated in “Differential tables calculation for an OPEN-V volume” (page 20) , the number of
differential tables required for each migration plan for an OPEN-3 volume is 3, and the number
of required pair tables for each migration plan is 1. If you want to create 20 migration plans of
OPEN-3 volumes, 60 differential and 20 pair tables are required. These numbers are plugged into
the original equation:
[ (3 x 20) = 60 ] ≤ 26,176 and [ (1 x 20) = 20 ] ≤ 8,192
Because this expression is true, you can create all 20 migration plans for the OPEN-3 volumes.
In the preceding calculation, it is assumed that only Auto LUN is running. However, as mentioned
earlier, differential tables are resources that are also shared by Business Copy, Business Copy Z,
and Compatible FlashCopy. The total number of pair tables used by Business Copy, Business Copy
Z, Compatible FlashCopy and Auto LUN should be within the value of (β) and (δ). For details on
how to calculate the number of differential tables and pair tables used by the programs other than
Auto LUN, see the manuals of the corresponding products.
22 Auto LUN planning