vSphere Essentials and Essentials Plus are kits designed with the SMB space in mind and are getting started with virtualization. These kits also include vCenter Server unlike when purchasing vSphere Standard, Enterprise, etc. where the vCenter Server license is purchased separately. The vCenter Server version included with vSphere Essentials and Essentials Plus is called “vCenter Server for Essentials“. vCenter Server for Essentials is similar to Foundation in terms of its feature limitations. When bundled with vSphere Essentials, vCenter Server for Essentials allows for management of up to three vSphere ESXi hosts, with up to two physical CPUs each. There is no support for vMotion or vSphere High Availability with vSphere Essentials. The creation of datacenters, clusters, etc. are available but migrations to other hosts would require a “cold migration” or powered off VM prior to migrating.
When vSphere Essentials Plus is purchased it also comes with vCenter Server for Essentials which allows for business continuity features such as, vSphere High Availability (HA) and vMotion. vSphere Essentials Plus also unlocks cross switch vMotion, vSphere Replication, and optional access to VSAN.