SnapMirror replication relies on a matching snapmirror-label to identify which snapshots to transfer. This label must be defined in two places: first, in the snapshot policy on the source volume that creates the snapshots, and second, in the SnapMirror policy on the destination that governs the replication relationship. If the SnapMirror policy, which is managed on the destination (secondary) cluster, lacks a rule specifying the correct snapmirror-label, the replication engine will not select any snapshots for transfer from the source, resulting in an empty destination volume as described.

B. If SnapMirror were not properly licensed, the creation of the SnapMirror relationship would have failed initially. The scenario implies the relationship was successfully created.

C. Incorrect SVM peering would prevent the SnapMirror relationship from being created. The problem states the relationship exists but is not transferring data.

D. The snapshot policy on the secondary (destination) volume is irrelevant for replicating data from the primary. The snapmirror-label must be in the snapshot policy on the source volume.

1. NetApp ONTAP 9 Documentation, "How SnapMirror replication works with Snapshot copies": "For a Snapshot copy to be replicated, it must have a SnapMirror label that matches one of the labels in the SnapMirror policy. The SnapMirror label is configured as part of the Snapshot policy on the source volume." This confirms the dual requirement for the label on both the source snapshot and the destination's SnapMirror policy.

2. NetApp Technical Report TR-4015, "SnapMirror Configuration and Best Practices Guide for ONTAP 9.3", Section 3.1, Page 10: This section details SnapMirror policies, stating, "The SnapMirror policy defines the contents of the Snapshot copies that are stored on the destination volume... A SnapMirror policy has one or more rules, and each rule defines a SnapMirror label and the number of Snapshot copies with that label to retain on the destination." This highlights that the SnapMirror policy itself must contain the label.

3. NetApp ONTAP 9 Commands Manual Page Reference, snapmirror policy create: The syntax for creating a policy rule that replicates specific snapshots includes the -snapmirror-label parameter. For example: -rules -snapmirror-label . Omitting this parameter means the rule will not match any labeled snapshots for replication.