How is the Dell EMC Unity Data Reduction Ratio calculated?

Divide the predate-reduction size of all storage resources and their snapshots by the postdata-reduction size of all storage resources and their snapshots.

Add up the efficiencies gained from thin provisioning, Deduplication, and Compression.

Divide the predate-reduction size of all storage resources excluding their snapshots by the postdata-reduction size of all storage resources excluding their snapshots.

Add up the efficiencies gained from thin provisioning, Snapshots, and Compression.