VMware Virtual SAN (vSAN) is a distributed layer of software that runs natively as a part of the ESXi hypervisor. Virtual SAN aggregates local or direct-attached capacity devices of a host cluster and creates a single storage pool shared across all hosts in the Virtual SAN cluster.
While supporting VMware features that require shared storage, such as HA, vMotion, and DRS, Virtual SAN eliminates the need for external shared storage and simplifies storage configuration and virtual machine provisioning activities.