Product : VMware, vSAN [SDS]/7.0 U1, Enterprise
Feature : Dedup/Compr. Type, Efficiency, Data Services
Content Owner:  Herman Rutten
Summary
All-Flash: Optional
Hybrid: N/A
Details
Compression occurs after deduplication and just before the data is actually written to the persisent data layer.

In vSAN 7.0 U1 and onwards there are three settings to choose from: "None", "Compression Only" or "Deduplication".

When choosing "Compression only" deduplication is effectively disabled. This optimizes storage performance, resource usage as well as availability. When using "Compression only" a single disk failing no longer impacts the entire disk group.