Summary

Any downtime, either planned or unexpected, means financial losses. With the virtualization technologies available today, it becomes easier to provide higher levels of availability for environments where they are needed. vSphere HA is a feature that allows a group of hosts connected together to provide high levels of availability for VMs running on these hosts.

Admission control ensures that there are sufficient resources available for failover protection as and when VM resource reservations are kept. It is available for hosts, resource pools, and vSphere HA.

HA offers only a basic level of protection; in the event of a host failure, it restarts the VMs. vSphere FT provides a higher level of availability and protects VMs from host failure without any downtime, or any loss of data, transactions, or connections.