Creating the sysplex root file system

The sysplex root is a file system that is used as the sysplex-wide root. This file system must be initially mounted read/write and designated AUTOMOVE. (See Customizing BPXPRMxx for a shared file system for a description of the AUTOMOVE parameter in BPXPRMxx.) Only one sysplex root is allowed for all systems participating in a shared file system.

The sysplex root is created in one of two ways:

For the zFS file system, it is created by invoking the BPXISYZR job in SYS1.SAMPLIB.
For the HFS file system, it is created by invoking the BPXISYSR sample job in SYS1.SAMPLIB.

After the job runs, the structure of a sysplex root file system would look like Figure 1:

Figure 1. What the file system structure of a sysplex root looks like After the job runs, the sysplex root consists of directories and symbolic links only.

After the job runs, the sysplex root consists of directories and symbolic links only.

No files or code reside in the sysplex root file system. It consists of directories and symbolic links only, and hence the size of the data set representing the sysplex root is very small.

The sysplex root provides access to all directories. Each system in a sysplex can access directories through the symbolic links that are provided. Essentially, the sysplex root provides redirection to the appropriate directories.

Guideline: After you create the directories for each system-specific file system and the version root file system, use the TSO UNMOUNT command to remount the sysplex root as read-only. Remounting the sysplex root file system as read-only prevents accidental corruption or full-file system problems with the sysplex root, both of which might require a sysplex IPL to recover. Additionally, most configurations will show improved performance if the file system is mounted as read-only. If a new directory needs to be added to the sysplex root file system, you can do the following tasks without disrupting the availability of the file system:

Use the TSO UNMOUNT command to remount the read-only file system to read/write mode.
Create the new directories.
Remount the file system in read-only mode.