1. A method to improve fault tolerance deployment strategy in a virtualized computing environment with a first fault domain and a second fault domain, the method comprising: determining whether a first primary virtualized computing instance and a first secondary virtualized computing instance are both in the first fault domain, wherein the first secondary virtualized computing instance is configured as a backup for the first primary virtualized computing instance and supported by a first host; in response to determination that the first primary virtualized computing instance and first secondary virtualized computing instance are both in the first fault domain, selecting a second secondary virtualized computing instance from the second fault domain, wherein the second secondary virtualized computing instance is configured as a backup for a second primary virtualized computing instance and supported by a second host; migrating the first secondary virtualized computing instance from the first host to the second host; and strategically migrating the second secondary virtualized computing instance from the second host to the first host, thereby swapping the first secondary virtualized computing instance in the first fault domain with the second secondary virtualized computing instance in the second fault domain.