ZFS HFS Z/os migrate

Q:

Why does JRB use an HFS not a ZFS? Can I migrate my HFS to a ZFS?

A:

ZFS is not a functional replacement for HFS. ZFS cannot be substituted for HFS for JRB. A directory traverse does NOT yield equivalent results on a ZFS. IBM is aware of this problem via requirement MR0608065439. 

On June 2006 we submitted requirement MR0608065439 to IBM: MR0608065439 (zFS should return a sorted list of filenames via the BPX1RDD syscall) IBM has yet to resolve this issue so for the time being JRB will remain on HFS.