MFE TF SnapVX: EQCA304E ERROR RETURNED FROM UNLINK SYSCALL, DATA3E-00080063

A RESTORE of B to B is performed after LINKING A to B. 

An UNLINK to a target device is performed but receives the following error message. The target device has an active RESTORE operation.
 

EQCA304E ERROR RETURNED FROM UNLINK SYSCALL, DATA3E=00080063

During a TERMINATE operation with AUTO_UNLNK specified, the same error may also appear:
 

EQCA304E ERROR RETURNED FROM UNLINK SYSCALL, DATA3E=00080063 

Also, the TERMINATE may return:
 

ESNP0FIE EMC SNAP API - CAN NOT TERMINATE SNAPSHOT DUE TO ACTIVE LINK

The error code indicates that a dependency is preventing the UNLINK operation. This typically means tracks are still owed to the device and must be resolved before the UNLINK can proceed.

x'0080063' is defined as SNAPVX_DEPENDENT_SNAPSHOTS_EXISTS

 The issue occurred when performing a CREATE of A, then a CREATE of B, LINKED A to B, and performed a RESTORE of B. After this, LINK of A to B fails, and UNLINK of either A to B or B to B returns the same error message.

The RESTORE was performed with MODE(NOCOPY) instead of MODE(COPY). This resulted in a dependent snapshot, which must be resolved before the target device can be overlaid.

From the TimeFinder SnapVX and zDP Product Guide:

If the linked target is in NOCOPY mode, a cascading snapshot is referred to as a
dependent snapshot. A target device cannot be unlinked without removing dependent
snapshots. Or, the snapshots should be removed in the reverse order of creation.
 
This definition process is not a physical copy operation, but rather a manipulation of in
memory track pointers. If the link operation was done in MODE(NOCOPY), then the
target and snapshot will be sharing physical tracks until a write is performed on the
target device. If the snapshot was linked in MODE(COPY), a subsequent background
copy process will copy the snapshot data and assign these new unshared tracks to the
target.

To remove the dependency, run a CONFIG command with MODE(COPY). This can be done either to directly remove the dependency or by performing RESTORE operations using MODE(COPY) to clear the LINK from B to B.

CONFIG(NAME(snapshotname) TARGET(UNIT(ccuu)) MODE(COPY)) 

Alternatively, to remove the dependency and allow the LINK of A to B to complete, use:
 

CONFIG(NAME(snapshotname) TARGET(SYMDV#(symdv#))  -
        LOCAL(UNIT(gatekeeper)) MODE(COPY))