IBM DS8000 manual Data migration planning, 183

DDM to DA Mapping -- 4-way

2
disk enclosure pair	2	6	3
(32 DDMs can be installed	2	6	3
2 means to attach to DA pair 2)
	0	4	1
0/1		4	1
I/O drawer	S0	7	2

(0/1 means device adapters	S1			7	2
for DA pair 0 and 1)					0
S0				5	0
Server	0/1	1/0	4/5	5/4
(0 means server 0)	2/3	3/2	6/7	7/6
disk enclosure pair	Base Frame		Expansion		Expansion
installation sequence
			Frame 1		Frame 2

Figure 9-14 DDM to DA Mapping (4-way model)

Model 922 can have eight DA pairs and 20 disk enclosure pairs.

Therefore, a 512 DDMs configuration is a well-balanced configuration (all eight DA pairs have 64 DDMs).

When you have the maximum number of DDMs (640 DDMs), DA pair 0 and 1 have 128 DDMs, and DA pairs 2 through 7 have 64 DDMs.

9.5 Data migration planning

When migrating data, the migration objectives should be clearly defined. Use the following key questions to define your generic migration environment:

￿Why is the data migrating?

￿How much data is migrating?

￿How quickly must the migration be performed?

￿What duration of service outage can be tolerated?

￿Is the data migration to or from the same type storage, for example from an ESS Model 800 to a DS8000?

￿What resources are available for the migration?

After answering these questions, you will be in a position to choose the appropriate tools and utilities, such as standard operating system mirroring, basic commands, software packages, remote copy technologies, and migration appliances to achieve your data migration objectives.

Chapter 9. Configuration planning 183