What does the term “HA cluster" refer to?

The term “HA cluster” refers specifically to a collection of ESXi hosts that work together to ensure high availability for virtual machines (VMs). This means that if one ESXi host in the cluster experiences a failure, the virtual machines running on that host can be automatically restarted on another host within the cluster. This capability significantly enhances the resilience of applications by minimizing downtime, ensuring that critical services remain available.

The concept of high availability is crucial in enterprise environments, as it not only protects against hardware failures but also improves overall system performance and reliability. In addition, HA clusters utilize shared storage, allowing VMs to be quickly migrated and restarted without data loss, which is a key benefit of VMware’s architecture.

In contrast, isolated network segments for VMs, backup solutions, and storage arrays do not define the core function of HA clusters, which primarily focus on maintaining uptime and minimizing disruption due to host failures. Thus, the understanding of an HA cluster as a collection of ESXi hosts aimed at ensuring high availability is essential for effective VMware management and infrastructure planning.