Setting up a ReadyNAS 214

Just pick LACP with layer-2 hashing.  FWIW, that is what the R8500 is using.  That gives the most predictable results (not always the best performance, just the most repeatable performance).

Here's the way it works:  The hashing is used by the NAS to decide which NIC card will send each data flow.  It's basically like a coin-flip.  So each data flow from the NAS to device X will always use only one NIC.  Also, since this is an xmit decision, the router also is making this decision, and it could choose a different NIC for the return traffic.  

Layer 2 uses the mac addresses of the NAS and the receiving device (which are hard-wired into the ethernet chips, and always are the same).  Layer 3 adds in the IP addresses (which will vary if you use DHCP).  Layer 3+4 adds in the TCP/UDP ports being used. That normally is only used if you are also using bonding in the receiving device.

There are a couple of implications.

One is that every data flow through the bond is limited to 1 gigabit.  That's because every flow uses just one NIC in the bond. That is by design - the assumption is that the clients aren't using a bonded connection, and you don't want to overrun their 1 gigabit connection.

Second, if you sending from the NAS to 2 devices there is a 50-50 chance that the NAS will use the same NIC for their xmit traffic.  If you look at both directions, there's a 75% chance that either the xmit or the receive traffic will share a NIC.  So the bond is often underutilitized if you only have a couple of devices.

Since the different hashes give different answers to the "coin flip" you can sometimes get a better NIC allocation with a different hash. That can improve throughput with specific devices (when you only have a couple).

But as far as streaming performance goes, it really doesn't matter much.   Streaming doesn't use as much bandwidth as most people think. Even full 1080p BluRay has a max of 54 mbits (8 megabytes per second).  Even without bonding, that's only about 5% of the link capacity.  And most HD streams aren't full BluRay - they are in the 1-2 megabytes per second range.  So the hash isn't something you need to over-think.