We ran into problems however with one system that would not run after the patch process. Booting normally led to kernel panic —
kernel panic not syncing
VFS: unable to mount root fs on unknown-block (0)

Booting into Debug mode or Service Console Only, the server worked fine. It checked the file system, and must have fixed the problem with the file system. It however complained on shutdown it could not save new initrds. The system now stopped as it attempted to load initrds when booting normally.

My choices were somewhat clear - call support or rebuild. I called VMware support, and this was apparently a common problem with the latest patches. Here was the fix:

Boot into ESX debug mode, and run the following commands.
* “esxcfg-boot -p” - to reload the PCI data
* “esxcfg-boot -r” - to refresh initrd information
* “esxcfg-boot -b” - to setup boot information

I have definitely put these commands in the toolbox for next time since they didn't seem to be documented anyplace else.