What is one characteristic of vSphere HA?

vSphere High Availability (HA) is designed to ensure maximum uptime for virtual machines by automatically restarting them on alternative hosts in the event of host failure, including situations where a host becomes isolated due to network issues. This characteristic is crucial in maintaining VM availability, as it swiftly addresses the problem of host isolation, which can prevent VMs on the isolated host from being accessed or managed.

When a host becomes isolated in the management network, vSphere HA takes action based on its failover policy to restart the affected VMs on other hosts within the cluster that are still operational. This capability is part of what makes vSphere HA a key feature for ensuring business continuity and minimizing downtime due to host failures.

The other options address aspects that are not closely related to the core functionality of vSphere HA. For instance, load balancing across hosts is primarily managed by vSphere Distributed Resource Scheduler (DRS), not HA. While backup for VMs is vital for data protection, this is not a function of HA; rather, it involves dedicated backup solutions. As for licensing requirements, while it's true that there might be costs involved with certain advanced features, basic HA functionality is generally included with standard licensing frameworks, making it accessible for production use without requiring additional licenses.