There is no issue with putting 3 EFD Disk packs in the same DAE.   For maximum performance from all the EFDs you may want to put some in a storage pool used by servers on SPA and some from servers on SPB (if that fits your use case).  Again, the max disk limit of 120 for a 3300 applies for EFDs as well.
Hi is there anything in the way of docuemntation that would describe any do's, dont's and general considerations for using EFD in the 3300?   I am keen to understand maximum counts per array, dae etc and also the distribution. Ie is a a good idea to place 3 EFD disk packs across one DAE? If not then what should the distribution be...  THanks  JB
VNXe 3300 EFD Best Practices