What is the minimum number of ESXi hosts required to support vCenter High Availability?

vCenter High Availability (HA) requires a minimum of three ESXi hosts to function effectively. This configuration involves one active instance of vCenter Server and two standby instances. The active instance is responsible for processing requests and managing the vSphere environment. In case of failure of the active node, one of the standby instances can take over, ensuring continuous availability of vCenter services.

The requirement for three hosts ensures that there is sufficient resource separation and redundancy, allowing the vCenter Server to maintain its functions even if one host fails. The use of three hosts also enables a quorum-based decision-making process, which is essential for maintaining availability and preventing split-brain scenarios. While other configurations may support different functionalities, vCenter HA has been specifically designed around this three-host requirement to ensure reliability and service continuity during hardware or software failures.