A typical VMware vSphere data center consists of basic physical building blocks such as x86 virtualization servers, storage networks and arrays, IP networks, a management server, and desktop clients.

The vSphere data center topology includes the following components.

Compute servers

Industry standard x86 servers that run ESXi on the bare metal. ESXi software provides resources for and runs the virtual machines. Each computing server is called a standalone host in the virtual environment. You can group a number of similarly configured x86 servers with connections to the same network and storage subsystems. This grouping creates an aggregate set of resources in the virtual environment, called a cluster.

Storage networks and arrays

Fibre Channel SAN arrays, iSCSI SAN arrays, and NAS arrays are widely used storage technologies supported by VMware vSphere to meet different data center storage needs. The storage arrays are connected to and shared between groups of servers through storage area networks. This arrangement allows aggregation of the storage resources and provides more flexibility in provisioning them to virtual machines.

IP networks

Each compute server can have multiple physical network adapters to provide high bandwidth and reliable networking to the entire VMware vSphere data center.

vCenter Server

vCenter Server provides a single point of control to the data center. It provides essential data center services such as access control, performance monitoring, and configuration. It unifies the resources from the individual computing servers to be shared among virtual machines in the entire data center. It manages the assignment of virtual machines to the computing servers and the assignment of resources to the virtual machines within a given computing server. These assignments are based on the policies that the system administrator sets.

Computing servers continue to function even in the unlikely event that vCenter Server becomes unreachable (for example, if the network is severed). Servers can be managed separately and continue to run the virtual machines assigned to them based on the resource assignment that was last set. After connection to vCenter Server is restored, it can manage the data center as a whole again.

Management clients

VMware vSphere provides several interfaces for data center management and virtual machine access. These interfaces include vSphere Web Client for access through a web browser or vSphere Command-Line Interface (vSphere CLI).