I’ve posted about vSphere HA advanced settings various times in the past, and let me start by saying that you shouldn’t play around with them unless you have a requirement to do so. But if you do, there is a KB article which I can highly recommend as it lists all the known and lesser known advanced settings. I had the KB article updated with vSphere 5.5 advanced settings yesterday (Thanks KB team for being so responsive!) but it also applies to vSphere 5.0 and 5.1. Recommended read for those who want to get in to the nitty gritty details of vSphere HA.
http://kb.vmware.com/kb/2033250
