SRDF/Star VILT, Activating Clone after transient failure

Depending on the microcode level if you try to simply create/recreate a TimeFinder/Clone against an SRDF/A R2 device without the -precopy option the operation will fail.

SRDF/A resiliency feature called Group Level Write pacing was introduced in 5874 and then a feature called device level Write Pacing was introduced in 5875 which has since been augmented in later microcode levels. Anyway if you enable Device Level Write Pacing then you will be allowed to create/recreate a TimeFinder/Clone session against the SRDF/A R2 without the -precopy option.

The -precopy option with TimeFinder/Clone create/recreate will allow the operation to succeed even without turning on device level write pacing for the SRDF/A R2 devices. So historically we have always used the -precopy option for the async target site when creating/recreating the TimeFinder/Clone session.

You can read more about SRDF/A write pacing in the  EMC Symmetrix Remote Data Facility (SRDF) Product Guide

and in the EMC Solutions Enabler Symmetrix SRDF Family CLI Guides.