HP XP Racks - Manual (Page 347)

4. From the secondary host, execute the YKRESYNC REVERSE command for the Cnt Ac-J Z copy
group (reverse copy direction).
5. Recover the applications on the secondary host.
Because volumes in the storage system at the remote site are not accessible, do not recover
the applications until you finish steps 1 to 5.
Failback Procedure
You cannot perform a failback until Continuous Access Synchronous Z and Continuous Access
Journal Z copy operations from the primary host are enabled.
To perform a failback in a 3DC Cascade (Cnt Ac-S Z x Cnt Ac-J Z) configuration:
Using a 3DC Cascade (Cnt Ac-S Z x Cnt Ac-J Z) Configuration 347