Product : VMware, vSAN [SDS]/7.0 U1, Enterprise
Feature : Deployment Architecture, Deploy, Design & Deploy
Content Owner:  Herman Rutten
Single-Layer (primary)
Dual-Layer (secondary)
Single-Layer: VMware vSAN is meant to be used as a storage platform as well as a compute platform at the same time. This effectively means that applications, hypervisor and storage software are all running on top of the same server hardware (=single infrastructure layer).

VMware vSAN can partially serve in a dual-layer model by providing storage also to other vSphere hosts within the same cluster that do not contribute storage to vSAN themselves or to bare metal hosts. However, this is not a primary use case and also requires the other vSphere hosts to have vSAN enabled (Please view the compute-only scale-out option for more information).