Here are some vSphere 5 issues. Be aware before upgrading to vSphere 5:
– ESXi 4.0 Update 2 hosts may experience a purple screen after vCenter Server is upgraded to 5.0
– ESXi 5.x boot delays when configured for Software iSCSI
Update 03-11-2011 VMware released a patch that solves this problem. More information can be found here.
– HP BladeSystem – Emulex be2net Inbox Driver Version 4.0.88.0 Does Not Support Flex-10 or Flex Fabric Adapters on VMware ESXi 5.0 in a Virtual Connect Environment and Emulex OneConnect driver not supported on vSphere 5.0 for HP hardware
Update 02-11-2011 HP has a new firmware and driver to fix this problem. More info can be found here.
– Disabling VAAI Thin Provisioning Block Space Reclamation (UNMAP) in ESXi 5.0
– VMware ESXi 5.0 – Unable to Add Host to vCenter After Applying a VMware License to a Host Running the HP Custom Image for VMware ESXi 5.0
Maybe also worth to take a look at it:
HA Error after Upgrading:
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2006210
Regards
Andi
@Andi Thanks for mention