Kassim
It all depends on the environment and what degree of oversubscription are you comfortable with between the IOM and the FI.
As you are already running UCS, I would start by looking at the current utilization to begin with.
The 2104 is characterized by 8 downlinks (server facing or HIFs) and up to 4 uplinks (FI facing or NIFs).
A starting config can be either 1, 2 or 4 links i.e 2^x number of links for static pinning.
Within UCS QoS can be configured so you can specify min bandwith guarantee at the time of congestion.
If you just want to get a feel for whats out there, most of the time I have come across 2 links per side.
Again, what I have seen most and not a best practise/guidance by any stretch.
Thanks
--Manish