KB Article: 3371739 (http://kb.vmware.com/kb/3371739
I think the above KB article could be help of you to understanding the limitation of VMFS LUN size.
I think you can create 2.7TB RAID6 volume but after that you should devide it into LUNs smaller than 2TB each. Then those LUNs (less than 2TB in size) will be presented to ESX host. Consult with storage documentation and/or support engineer on how to build RAID volume and create LUNs.
Hoefully this answers you.