Which feature allows VMs to have redundancy for uptime?

The feature that provides redundancy for uptime in a virtualized environment is Fault Tolerance. Fault Tolerance allows virtual machines (VMs) to run concurrently on different hosts while maintaining a primary and a secondary instance. This ensures that if the primary instance fails due to hardware or host issues, the secondary instance can seamlessly take over, providing continuous availability of the VM without any downtime.

Fault Tolerance works by continuously mirroring the state and operations of the primary VM to a secondary VM in real time. This means that the secondary VM is always ready to take over, thus enhancing the overall reliability and uptime of critical applications running within the VMs.

In contrast, features like VM Snapshots are primarily used for backup and recovery purposes rather than continuous redundancy, while Resource Pools are a way to manage and allocate resources among VMs, and High Availability ensures that VMs can be quickly restarted on another host in the event of a failure but does not provide the same level of real-time redundancy as Fault Tolerance. Thus, Fault Tolerance is specifically designed to maintain uptime by allowing VMs to function without interruption.