Problem solve Get help with specific problems with your technologies, process and projects.

Setting up auxiliary storage pools

Is it possible to dedicate a certain area on the disk for a specific application? (This would improve performance as in mainframes.)

The OS/400 doesn't directly support the placement of objects in auxiliary storage. However, you can create up to 15 auxiliary storage pools (2-16) commonly referred to as ASP's, and then place groups of objects in these ASP's by putting them into a library created in an ASP.

For complete instructions on how to create a new ASP refer to the following OS/400 manual: Title: OS/400 Backup and Recovery V4R5 Document Number: SC41-5304-04

Once an ASP is created you would then create a library in it. This is done by with the ASP parameter of the CRTLIB command: CRTLIB LIB(LIBNAME) ASP(2) This creates a library in ASP2

Putting any object into this library would result in it being stored on the disks assigned to ASP2.

Here is brief discussion of ASP's taken from the iSeries Information Center (V4R5): Auxiliary Storage Pools (ASPs) separate disk units into logical subsets, which can give you a number of advantages. Using ASPs helps protect your data. By separating libraries, documents, or other objects in an ASP, you protect them from data loss should a disk unit in a different ASP fail. You can protect each ASP individually, indicating the value you put on that data.

Using ASPs also increases performance. You can place libraries or objects in an ASP, allowing you to dedicate the disk units in the ASP exclusively for the use of those objects. If you do extensive journaling, a dedicated disk unit for the journal receiver can also improve journaling performance.

ASPs are used to manage system performance and backup requirements. You can create an ASP to provide dedicated resources for frequently used objects, such as journal receivers.

You can create an ASP to hold save files. Objects can be backed up to save files in a different ASP. It is unlikely that both the ASP that contains the object and the ASP that contains the save file will be lost.

You can create different ASPs for objects with different recovery and availability requirements. For example, you can put critical database files or documents in an ASP that has mirrored protection or device parity protection.

You can create an ASP to place infrequently used objects, such as large history files, on disk units with slower performance.

You can use ASPs to manage recovery times for access paths for critical and non-critical database files using system-managed access-path protection.

Dig Deeper on Performance