IASP

Resolving The Problem

An independent axillary storage pool is a collection of disk units that can be brought on-line or taken off-line independently from the remaining storage on a system, including the system ASP, basic user ASPs, and other independent ASPs. An independent ASP can be switchable between multiple systems in a clustered environment or privately connected to a single system.

The benefits, in both multi-system clustered environments and single-system environments, can be significant. For example, in a clustered environment, the use of independent ASPs can provide disk storage that is switchable between servers in the cluster, providing continuous availability of resources. In a single-system environment, independent ASPs could be used to isolate infrequently used data that does not always need to be present when the system is operational.

System ASP

One system ASP exists per IBM iSeries family of servers. The system automatically creates the system ASPl (ASP 1) that contains disk unit 1 and all other configured disks that are not assigned to a basic or independent ASP. The system ASP contains all system objects for the operating system licensed program and all user objects that are not assigned to a basic or independent ASP.

User ASP

There are basic ASPs and independent ASPs. A basic user ASP can be created by grouping a set of DASD units together and assigning that group to ASP. Configure basic ASPs with numbers 2 through 32. Independent ASPs are numbered 33 through 255. In a clustered environment, independent ASPs can be switched between systems without having to perform an IPL allowing for continuously available data.

Basic ASP

A basic ASP is used to isolate some objects from the other objects that are stored in the system ASP. Basic ASPs are defined by the user. Data in a basic user ASP is always accessible whenever the server is up and running. When storage for a basic ASP is exhausted, the data can overflow into the system ASP. This is different from an independent ASP that does not allow data to overflow into the system ASP.

Independent Auxiliary Storage Pool (Independent ASP or IASP)

An independent ASP can be made available (varied on) and made unavailable (varied off) to the server without restarting the system. When an independent ASP is associated with a switchable hardware group, it becomes a switchable ASP and can be switched between one iSeries family server and another iSeries family server in a clustered environment. An independent ASP that is not associated with a cluster resource group is referred to in operating system application programming interfaces (APIs) as a private ASP. Independent ASPs can also function in conjunction with other independent ASPs in a ASP group. The following definitions describe the types of independent ASPs. There are: user-defined file system, primary, and secondary.

User-Defined File System (UDFS)

An independent ASP that contains only user-defined file systems cannot be a member of a ASP group unless it is converted to a primary or secondary ASP.

Primary IASP

An independent ASP that defines a collection of directories and libraries and may have secondary IASPs associated with it. A primary ASP also defines a database for itself and other secondary IASPs, that may be added in its ASP group. Primary ASPs can be implemented only on R520 or later of OS/400.

Secondary IASP

An independent ASP that defines a collection of directories and libraries, and must be associated with a primary IASP. A possible use for a secondary IASP is to store journal receivers for the objects being journaled in the primary ASP. Secondary ASPs can be implemented only on R520 or later of OS/400.

For more information, see the IASP section of the Information Center at the following URL:

http://publib.boulder.ibm.com/iseries/v5r2/ic2924/info/rzaly/rzalyiasptypes.htm