Deduplication allows a storage system to find duplicate blocks in its file system and then create pointers to a single block to reduce the total amount of used capacity. In unified ONTAP, deduplication follows a specific boundary for what blocks can be reduced. Those boundaries depend on the type of deduplication in use. In general:

Unified ONTAP deduplication domains

Because NetApp AFX removes physical aggregates and moves capacity management to the new Storage Availability Zone, the deduplication domain boundaries also change. In AFX, the deduplication domain is at the volume-level (like unified ONTAP) and the node (rather than the aggregate) prior to 9.19.1.

Starting in ONTAP 9.19.1, AFX supports a global deduplication domain at the Storage Availability Zone level, so all duplicated blocks in the cluster storage pool are treated the same.

NetApp AFX – Global deduplication domain (ONTAP 9.19.1)

The table below compares capacity behaviors for duplicated data in different scenarios. As file copies span nodes and aggregates (and thus, deduplication domains) in unified ONTAP, space savings get reduced. In AFX prior to 9.19.1, the same happens when copies span nodes. Starting in 9.19.1, global deduplication applies the same savings across the Storage Availability Zone.

Deduplication behaviors for identical 10GB files – unified ONTAP and NetApp AFX