vSAN is a hyper-converged, software-defined storage (SDS) that creates a pools of storage using (DAS) direct-attached storage devices. You can use the vSAN datastore to deploy and run VMs on it.
In general to use vSAN you need:
1. Minimum of three ESXi hosts for standard datacenter deployments.
2. VMware vCenter Server. Minimum 6.0 but latest is preferred.
3. At least one device for the capacity tier and one flash device for the cache tier
4. One boot device to install ESXi.
5. Dedicated network port for vSAN–VMkernel interface.
A great place to start learning or get to know more about vSAN i recommend to have a look at: