Here is the most awesome ESX script known to mankind (by mankind I mean me) ever in the history of time (by ever I mean at least this week).
SnapVMX by Mr Ruben Garcia
I’ve being driving myself crazy over the last week trying to manually re-chain some horribly complicated and completely broken snapshots. This script (under a GPL3 license) analyses the complete snapshot chain and tells you exactly where there are broken links or missing files. It even reports exactly how much space you’ll need on the home datastore to commit them all. All automagically.
I was going to follow the link to this script with a detailed explanation of how snapshots work, how they commonly break and of course how to fix up the mess. However, it seems the author of the SnapVMX script has also written a paper (under a Creative Commons license) explaining the details more effectively than I could. It’s great read if you want to learn more about the inner workings.
Troubleshooting Virtual Machine snapshot problems by Mr Ruben Garcia
It even explains how to commit the individual disks of a VM, if room is tight on the datastore. And has this nice flowchart to help suppress the inevitable panics when the snapshots go South.
Rubian – if you make it VMworld this year, please make yourself known to me to redeem your free beer token.