Specifying ASP (Auxiliary Storage Pool) for the IFS

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February 5, 2009

Another golden oldie from the bucket full of dusty emails sitting in the corner… hopefully useful to somebody who doesn’t know that ASP stands for Auxiliary Storage Pool:

IBM Support Line Technical Document

Specifying Auxiliary Storage Pool When Using IFS

Document Description:
IFS commands such as MKDIR and IFS APIs do not provide an option to specify which ASP to use. This is because UNIX/POSIX APIs, on which IFS APIs are based, do not have a concept of ASP. The following steps show how you can use a particular ASP when using IFS APIs or commands on an AS/400e or iSeries 400 system.

To determine if you have multiple ASP on the AS/400e or iSeries 400 system, on the OS/400 command line type the following:


Press the Enter key. Select Option 5 to move to the Next Level.

If your system has only one ASP, you will see only QASP01. Otherwise, you will see additional QASPnn links.
You can have as many as 98 user ASPs plus one system ASP on the AS/400e or iSeries 400 system.

Before you can use a particular Auxiliary Storage Pool from IFS, an User-Defined File System (UDFS) must be created in that ASP.

Auxiliary Storage Pool To create the UDFS on the OS/400 command line, type the following:


1 Run the above command one time only.
2 To have the file system case-sensitive, select *MIXED; however this is not recommended. This command creates an User-Defined File system called ASP02 in ASP02.
3 Before using this file system it must be mounted using the Mount command. Mount is not preserved across IPLs. Therefore, you must mount after every IPL. It is recommended that you place the Mount command in the start-up program for the system.
To mount the User-Defined File System on a object-link ‘\M1’, type the following on the OS/400 command line:


To create Object-link M1, type the following:


It is recommended that you do not use Object-Link ‘\M1’ when the file system is not mounted. If you created Object Links under ‘\M1’, those are no longer available when the UDFS is mounted over this directory.

Once the UDFS is mounted you can create new links that will be stored in ASP02. For example,
the following command creates a directory in ASP02, and the second command copies a CL source file there:



The file system is unmounted during IPL or you can use the following command when you are done:



IBM i Software Developer, Digital Dad, AS400 Anarchist, RPG Modernizer, Shameless Trekkie, Belligerent Nerd, Englishman Abroad and Passionate Eater of Cheese and Biscuits. Nick Litten Dot Com is a mixture of blog posts that can be sometimes serious, frequently playful and probably down-right pointless all in the space of a day. Enjoy your stay, feel free to comment and remember: If at first you don't succeed then skydiving probably isn't a hobby you should look into.

Nick Litten

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