Observe the following best practices for allowing proper interoperability between vSphere HA and other features.
vSphere HA and Storage vMotion Interoperability in a Mixed Cluster
In clusters where ESXi 5.x hosts and ESX/ESXi 4.1 or prior hosts are present and where Storage vMotion is used extensively or Storage DRS is enabled, do not deploy vSphere HA. vSphere HA might respond to a host failure by restarting a virtual machine on a host with an ESXi version different from the one on which the virtual machine was running before the failure. A problem can occur if, at the time of failure, the virtual machine was involved in a Storage vMotion action on an ESXi 5.x host, and vSphere HA restarts the virtual machine on a host with a version prior to ESXi 5.0. While the virtual machine might power on, any subsequent attempts at snapshot operations could corrupt the vdisk state and leave the virtual machine unusable.
Using Auto Deploy with vSphere HA
You can use vSphere HA and Auto Deploy together to improve the availability of your virtual machines. Auto Deploy provisions hosts when they power up and you can also configure it to install the vSphere HA agent on such hosts during the boot process. See the Auto Deploy documentation included in vSphere Installation and Setup for details.
Upgrading Hosts in a Cluster Using Virtual SAN
If you are upgrading the ESXi hosts in your vSphere HA cluster to version 5.5 or higher, and you also plan to use Virtual SAN, follow this process.
Upgrade all of the hosts.
Disable vSphere HA.
Enable Virtual SAN.
Re-enable vSphere HA.