HP XP P9500 Storage - Manual (Page 22)

Running concurrent manual migration plans
The number of manual migration plans that can be executed concurrently depends on the following
conditions:
•
The amount of shared memory available for differential tables. You can install additional
shared memory for differential tables. If additional shared memory for differential tables is
installed, you may use 104,768 or 209,600 differential tables.
To install additional shared memory for differential tables, call HP Technical Support.
•
The amount of shared memory available for pair tables. You can install additional shared
memory for pair tables. You may use 16,384 pair tables if additional shared memory for pair
tables is installed.
To install additional shared memory for pair tables, call HP Technical Support.
•
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 manual 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 Snapshot, Business Copy, Business
Copy Z, and Compatible FlashCopy. The total number of pair tables used by Business Copy,
Business Copy for Mainframe, 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.
Fixed parity groups
If the Auto Migration function is enabled, some volumes and parity groups might experience
degraded I/O speeds. For example, if volume 00:00:01 is migrated from the parity group Grp1-1
of class A to the parity group Grp-2-1 of class B, volume 00:00:01 is migrated to a lower-speed
hard disk drive and might suffer a delay in I/O speed. If you specify Grp1-1 as a fixed parity
22 Auto LUN planning