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276 DS8000 Series: Concepts and Architecture
Figure 12-14 Extent pool affinity to processor complex with pooled ranks in two extent pools
Again what is obvious here is the affinity between all volumes residing in extent pool 0 to the
left processor complex, server 0, and vice versa for the volumes residing in extent pool 1 and
their affinity to the right processor complex or server 1.
When creating volumes there is no straightforward approach to place certain volumes into
certain ranks. For example, when you create the first 20 DB2 logging volumes, they would be
allocated in a consecutive fashion in the first rank. The concerned RAID site would then host
all these 20 logging volumes. Now with AAL and the high performance and large bandwidth
capabilities of the Fibre Channel switched disk storage subsystem, this might not be an issue.
You may choose to control the placement of your most performance-critical volumes. This
might lead to a compromise between both approaches, as Figure 12-14 suggests.
Plan for a reasonable number of extent pools
Figure 12-15 presents a grouping of ranks into extent pools which follows a similar pattern
and discussion as for grouping volumes or volume pools into SMS storage groups.
RIO-G ModuleRIO-G Module
HA
8
6
12
10
4
2
Extent pool1
7
5
11
9
31
Extent pool0
Rank
DAs
RIO-G Module
POWER5 2-way SMP
Server0
Memory
L3
Memory
Processor
Processor
L1,2
Memory
L1,2
Memory
RIO-G Module
POWER5 2-way SMP
Server1
Memory
L3
Memory
Processor
Processor
L1,2
Memory
L1,2
Memory