VMware has released a Frequently Asked Questions paper on vSphere Flash Read Cache. The FAQ which contains 5 Pages provides answers to 67 questions on the Flash Read Cache functionality.
vSphere Flash Read Cache, which is a new feature of vSphere 5.5 enables the pooling of multiple Flash-based devices into a single consumable vSphere construct called a Virtual Flash Resource. The Virtual Flash Resource is consumed and managed in the same way CPU and memory are done today in vSphere. For more information about Flash Read Cache, please see: What’s New in VMware vSphere Flash Read Cache