This is from Wen, @Wensteryu, Nimble Storage Technology Evangelist.
We have gotten lots of customer inquiries in learning more about VMDK vs. RDM vs. in-guest attached iSCSI storage, and its implication on data protection with Microsoft VSS framework/integration. Instead of telling you what to do directly, I decided to work with our engineering gurus (Jay Wang, Anagha Barve, Sathya Bhat and Scott Moreland) who think about this day in and day out, to do a joint two part post on how VSS works, follow by design considerations….