This is something that I was unaware of until recently when I was looking into the usage of V-Vols. It appears that VMware have made some major improvements to the ways we handle snapshots and consolidate them in vSphere 6.0 with VVols. Most people who use VMware are aware of limitations with snapshots on VMs that have heavy IO or large snapshots attached to them. In a large number of cases we see snapshots fail to remove and then require hours of downtime to actually consolidate.
Recently I have seen an issue after upgrading some of our Dell R6xx hosts to 5.5 U2, they started showing FCoE in the storage adapters and booting took a really long time.
I looked into this and found that the latest Dell ESXi image also includes Drivers and scripts that enable the FCoE interfaces on cards that support it.
To see if you have this problem check the below steps:
This is a very short and sweet article documenting the offline upgrade process from 5.5 to 6.0