What is the role of vSphere High Availability (HA)?

vSphere High Availability (HA) plays a critical role in maintaining the uptime and availability of virtual machines (VMs) within a VMware environment. Its primary function is to provide a failover capability for VMs during host failures. When a physical host fails, vSphere HA automatically detects the failure and restarts the affected virtual machines on other available hosts within the cluster, ensuring minimal downtime and maintaining service continuity. This capability is essential for organizations that require high availability for their applications and workloads, as it reduces the risk of service interruption caused by hardware failures.

The other choices relate to different functionalities within the virtualization environment. Optimizing network traffic is more aligned with features like Distributed Switch or Network I/O Control, while enhancing VM performance through resource allocation pertains to resource management features in vSphere, such as Distributed Resource Scheduler (DRS). Managing VM backups and restores involves data protection tools like VMware vSphere Data Protection or third-party backup solutions, which focus on data retention and recovery rather than on immediate failover during host outages.