Migrating the HFS file system to the zFS file system

Because zFS has higher performance characteristics than HFS and is the strategic file system, you should migrate HFS file systems to zFS. See z/OS Migration for more information about the migration action.

To compile a list of all mounted HFS file systems, use the USS_HFS_DETECTED check. For more information about the check, see IBM Health Checker for z/OS: User's Guide.

You can use the BPXWH2Z tool to migrate HFS file systems to zFS file systems. With this ISPF-based tool, you can change the space allocation, placement, SMS classes, and data set names. Invoke it from the ISPF command panel.

Requirement: The zFS address space must be successfully configured and initialized before you can use the BPXWH2Z tool. For more information about the customization and initialization of zFS, see the topic on post-installation processing in z/OS Distributed File Service zFS Administration.

To summarize, you can accomplish the following tasks with BPXWH2Z:

Migrate HFS file systems (both mounted and unmounted) to zFS file systems. If the HFS being migrated is mounted, BPZWH2Z automatically unmounts it and then mounts the new zFS file system on its current mount point.
Define zFS aggregates by default to be approximately the same size as the HFS file system. The new allocation size can also be increased or decreased.
Have the migration run in TSO foreground or UNIX background.

You can use the JCL sample ISPBTCH in SYS1.SAMPLIB to invoke BPXWH2Z as an ISPF batch job. Read the notes section before running the job. If you manually migrate from an HFS to a zFS file system without using the BPXWH2Z tool, you must allocate and format the target zFS file systems.