What is the correct sequence of actions performed by a PowerMax when the SRDF failback command is executed?

A TimeFinder SnapVX snapshot of source volumes has been linked to target volumes. The target volumes are being used for application testing.
What should be done prior to a relink operation?
A PowerMax systems administrator has created three storage groups with the diamond, gold, and silver service levels. How does the system ensure the service level response times are met during heavy workloads?
When using TimeFinder SnapVX, what is the maximum number of linked targets allowed per source?
What is a minimum requirement for Dell EMC VSI 8.0 on a VMAX All Flash array?