Types of disk pools

 

There are several types of disk pools.

Fundamentally, a disk pool, also referred to as an auxiliary storage pool (ASP), is a software definition of a group of disk units on your system. This means that a disk pool does not necessarily correspond to the physical arrangement of disks. Conceptually, each disk pool on your system is a separate pool of disk units for single-level storage. The system spreads data across the disk units within a disk pool.

There are two main types of disk pools: system disk pools (system ASPs) and user disk pools (user ASPs). The two types of user disk pools are basic disk pools and independent disk pools. Independent disk pools are divided into primary disk pools, secondary disk pools, and UDFS disk pools. The following example and definitions explain the types of disk pools:

• System disk pool
  One system disk pool exists per system. The system automatically creates the system disk pool (Disk Pool 1), which contains disk unit 1 and all other configured disks that are not assigned to a basic or independent disk pool. The system disk pool contains all system objects for the i5/OS^® licensed program and all user objects that are not assigned to a basic or independent disk pool.

• User disk pools
  There are two types of user disk pools: basic disk pools and independent disk pools. You can create a user disk pool by grouping a set of disk units together and assigning that group to a disk pool (ASP).

• Basic disk pools
  A basic disk pool is used to isolate some objects from the other objects that are stored in the system disk pool. Basic disk pools are defined by the user. Data in a basic user pool is always accessible whenever the system is up and running.

• Independent disk pools
  An independent disk pool is a disk pool that contains objects, the directories or libraries that contain the objects, and other object attributes such as authorization and ownership attributes.

• Primary, Secondary, UDFS disk pools
  An independent disk pool that contains user-defined file systems, directories and libraries, or associated directory and library information.

• Disk pool groups
  A disk pool group is made up of a primary disk pool and zero or more secondary disk pools. Each disk pool is independent in regard to data storage, but in the disk pool group they combine to act as one entity.

 

Parent topic:

Disk pools

Related reference
Independent disk pool terminology