In the past 3 months, this has happened twice and I need to know if I have something configured incorrectly.
Esxi 4.1 running on Server 2008 box with 3 guests (VM's). Due to a storm our power went off and we have the server on a UPS so it can shutdown gracefully. The other servers on the same UPS work fine. But on the console for Esxi, we get an error: PANIC: error reading file -3 s.z and after researching I found I had to boot from the CD and do a repair. Then we have to add back datastore to inventory, add the license key again, reassign the correct IP, etc.
So, I learned how to recover from this, but why does it become corrupt after a power outage. Once we repair Esxi etc...we are good to go.