Did you read any of the articles here:
vmwa.re/vsan
This article explicitly explains how to set it up in a nested environment:
Testing vSphere Virtual SAN in your virtual lab with vSphere 5.5
A proof of concept guide can be found here:
Virtual SAN POC Guide
Duncan
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Book out soon: Essential Virtual SAN: Administrator's Guide to VMware VSAN (VMware Press Technology)
