Determining why FlashCopy cannot be used

There may be times when you expect DFSMSdss to use FlashCopy® to move the data but FlashCopy was not used. As far as you can tell, your data sets meet the criteria for FlashCopy use. Use the DEBUG(FRMSG (MINIMAL | SUMMARIZED | DETAILED)) keyword to help you resolve this situation. Include this keyword to indicate the applicable fast replication message level (MIN, SUM, or DTL) in your COPY command. The message level controls the type and amount of information that DFSMSdss provides.

DEBUG(FRMSG(MIN | SUM | DTL)) dircts DFSMSdss to issue an informational message that indicates why FlashCopy or Preserve Mirror was not used. When you specify FASTREPLICATION(REQUIRED), DFSMSdss issues an informational message in addition to the ADR938E message, whether you have specified the DEBUG(FRMSG(MIN | SUM | DTL)) keyword or not.

Note:

The DEBUG(FRMSG) keyword might not have an effect if the target of the FlashCopy operation is not a PPRC primary device
If you specify FASTREPLICATION(REQUIRED) without specifying the DEBUG keyword, DFSMSdss still issues an informational message whenever a fast replication method cannot be used.
The DEBUG(FRMSG) keyword overrides the DEBUG=FRMSG parameter specified on the JCL EXEC statement.

For more information about the DEBUG keyword, refer to z/OS DFSMSdfp Storage Administration.