Extent Pool
10
37
10
01
0
5
0
1
1GB Extents
Ranks formated for FB data
Figure 9-2 Diagram of an extent pool containing 3 volumes
In Figure
Different volumes on a single extent pool can be assigned to the same or different LSSs.
Extent pools are assigned to server 0 and server 1 during configuration and receive their server affinity at this time. If you are using the custom configuration, we recommend, for user manageability reasons, that the client associate the rank even numbers to server 0 and the rank odd numbers to server 1 when defining the extent pools during the configuration process.
When creating extent pools, certain rules apply as follows:
A minimum of two extent pools must be configured to utilize server 0 and server 1.
More than one rank can reside in an extent pool, but two extent pools can not be made out of only one rank. We recommend that one extent pool be created out of one rank, unless the LUN capacity is greater than the capacity of one rank in the extent pool.
Some general considerations are:
One rank per pool will not constrain addresses.
Ranks can be added to an extent pool at any time.
The logical volumes defined in one extent pool can be in different LSSs.
The logical volumes in different pools can be in the same LSS, limited only by the odd and even server affinity.
Ranks can be removed from an extent pool if no extents on the rank are currently assigned to the logical volumes.
Chapter 9. The DS Storage Manager: Logical configuration 155
