Typically, you assign volumes to storage pools based on their common characteristics, such as device capabilities (availability or performance level) and usage (business division, project, application, location, or customer).
Each storage pool manages its own volumes. File space is allocated to the volumes in a given storage pool in a round-robin algorithm (as shown in Figure 1) in logical partitions, or in blocks. Logical partitions are allocated to the system storage pool in 16-MB blocks. For user storage pools, including the default storage pool, you can allocate logical partitions in 16, 64, or 256-MB blocks. All logical partitions in the same storage pool must be the same size.
Parent topic: Storage pools