VMware vSphere High Availability protects against physical host failures and restarts failed virtual machines using a third-party load balancing virtual appliance or the solution based on vCloud Networking and Security Edge. This affords about 99.9% uptime for the load balancing functionality (based on vSphere HA availability numbers).

You can improve availability for the load balancer by running it in native high availability mode. This affords the edge an almost instantaneous failover, with session preservation.