My ESXi box’s boot disk died today. Massive filesystem errors while trying to install the latest security update. Thankfully I’ve had the VMware Management Assistant appliance running regular backups of the configuration, so it wasn’t too tough to restore. I grabbed a spare SATA drive that I had laying around (yeah, I know, it’s overkill), got it hooked up, installed and patched ESXi to the same revision, and restored the latest config backup. All the VMs are on the RAID volume so it was all up and running like nothing happened. So unless you’re using vSphere Auto Deploy you really should be backing up your ESXi configuration and have a physical machine that can restore that data.