Most of the time your HA issues are going to be DNS related. So ensure that your vcenter can ping all your hosts by FQDN without issue. In some cases though a stubborn server may not want to play the game even when everything is configured properly.
This method is considered a “last effort” as you’ll need to run some CLI commands on the ESX box. But i have found it useful in a few situations.
I’ve had some problems since my upgrade to virtualbox 2.2.0 on OpenSolaris. After some time all of my linux boxes seem to just die. The virtual machine just stops responding. Strangely there was no problem with my windows vms after the update.
From what i can tell it looks like the upgrade turned off “IO APIC” - this is the bit that seemed to cause the problem. Re-enabling this on all of my linux boxes seems to have fixed the problem. I’ll continue testing for another week and update this post if any problems re-occur.