datacenter traffic distribution

   I'm wondering if there's a reliable and public survey, statistics about
   the distribution of datacenter (or cloud, if you wish) traffic,
   according to protocols or traffic types? E.g. the share of
   iscsi/fcoe/etc in storage, or the share of TCP/UDP, and so on.
   For general, Internet traffic, i've found several, for example:
   - Cisco Visual Networking Index,
   - Arbor Networks survey,
   I'd be interested in seeing something similar for datacenter traffic,
   for research purposes.
   Thanks for you help in advance,