Adding a system-specific or version root file system to your shared file system configuration

In general, the contents of the sysplex root should only change when you need a new version root or system-specific root file system directory for your shared file system configuration. When a system is IPLed (initialized), the mount processing for the sysplex root file system will include defining the appropriate $SYSNAME or $VERSION directory in the sysplex root file system if the sysplex root is mounted as read/write. Assuming that you have the sysplex root file system mounted as read-only, the procedure to use to create a new version root or system-specific file system directory is as follows:

Use the following TSO command to change the file system from read-only to read/write mode:
```
UNMOUNT FILESYSTEM('Sysplex.Root.File.System.Name') REMOUNT(RDWR)
```
IPL the new system. When OMVS is initialized on the new system, the new directories will be defined automatically. If the system is already active, you can manually define the appropriate directories using ISHELL or the shell mkdir command.
To change the file back to read-only mode, use the following TSO command:
```
UNMOUNT FILESYSTEM('Sysplex.Root.File.System.Name') REMOUNT(READ)
```