In NetApp ONTAP, modern data replication relationships utilize the unified Extended Data Protection (XDP) SnapMirror engine. Under XDP SnapMirror and SnapVault architectures, the transfer of specific point-in-time Snapshot copies from a source volume to a secondary destination volume is strictly controlled by SnapMirror labels.

When a Snapshot policy creates local Snapshot copies on the source volume (e.g., hourly, daily, or weekly schedules), each scheduled snapshot can be tagged with an optional metadata string called a snapmirror-label. On the destination cluster, the applied SnapMirror policy contains rules that explicitly define which SnapMirror labels should be transferred and how many retention copies to preserve. If the hourly Snapshot copies on the source volume lack a SnapMirror label, or if their label does not match any rule defined within the destination volume's SnapMirror policy, the replication engine skips those snapshots entirely during scheduled transfers. A SnapMirror throttle restricts transfer bandwidth (KBps) but does not selectively filter snapshots. Tamperproof snapshots protect copies from deletion, and a cluster peering failure would block all replication transfers rather than selectively omitting hourly snapshots.