Add support for Cascading FlashCopy for COPY command with FASTREP(REQ) - see PTF UI172348

Context:

We take daily System Level backups (SLB) of our SAP production environments using the BACKUP SYSTEM utility.

We use Incremental FlashCopy to reduce the amount of data that needs to be physically copied to the FlashCopy target volumes and limit the pressure on the DASD subsystem.

We regularly perform Clones from our production systems into other systems, using the production FlashCopy disks as the source.

We use the COPY command with FASTREP(REQ) to guarantee that FlashCopy will be used.

Pain point:

We have to break the incremental relationship between the real production disks and their FlashCopy targets to allow us to perform the Clone. If we don't, we get the following type of error message when running the Cloning Tool COPY command:

CKZ02149E SOURCE VOLSER: F0368D ACTIVE IN COPY RELATIONSHIP

368D,3036,36,8D,2107,0000000KKA81,000001,065534,N,N,N

IS TARGET OF RELATIONSHIP

Having to break the incremental relationship causes:

(1) operational complexity

(2) negative impact on our application workloads during the next SLB as it will force a full physical background copy.

We meet all the prerequisites to exploit Cascading FlashCopy i.e. Clone without having to end the incremental relationships in the source system (see scenario 3b in attached document).

If we issue the COPY command with FASTREP(REQ) ourselves using ADRDSSU, the command runs successfully.

If we run the Cloning Tool with FASTREP(PREF), the COPY command runs successfully and uses FlashCopy -- but we do not want to use FASTREP(PREF) as it doesn't guarantee that FlashCopy will be used.

If we run the Cloning Tool with FASTREP(REQ), we are blocked by the initial check that looks for existing relationships.