Which service is required for fault tolerance protection in a vSphere environment?

In a vSphere environment, the VMware Fault Tolerance service is specifically designed to provide continuous availability for virtual machines. This service allows for a VM to run in lockstep with a secondary VM, providing a failover mechanism that ensures that if the primary VM fails, the secondary can immediately take over without any service disruption.

The design of VMware Fault Tolerance allows for zero downtime and no data loss by continuously replicating the state of the primary VM to the secondary VM, which is running on another host. This is particularly crucial for mission-critical applications that require high availability and cannot afford even a moment of downtime.

Other services mentioned, such as the Snapshot service, vCenter Server service, and VMware Tools service, serve different purposes. Snapshots are used for creating point-in-time copies of VMs for backup or testing. The vCenter Server service is essential for managing the vSphere environment but does not provide fault tolerance directly. VMware Tools enhances the performance and management of virtual machines but is not responsible for fault tolerance as a feature. Therefore, the VMware Fault Tolerance service is the correct choice for ensuring protection against faults in a vSphere environment.