Well, the open-e box can only use IP over Infiniband at the moment. Since you're using IP, it should be pretty simple.

I haven't done it, but we are looking to get some infiniband hca's in our lab soon (I don't work for open-e) to test it out, both with open-e's solution (IPoIB) and also with some other solution (random linux) using a sort of RDMA protocol (iSER or SRP or NFS-RDMA something else).

Unfortunately, with IP over Infiniband, you still have to use a lot of cpu to do all the IP processing. With RDMA, you can bypass the cpu for most transactions, so you're able to get much closer to the theoretical throughput of your interface. The downside is that you need to run iSER or something like that, instead of something that all computers basically support now (like NFS or SMB or iSCSI).

Another upside is that you can get a SDR (10Gbps) or DDR (20Gbps) infiniband card for less than 10Gb ethernet or 4Gb fibrechannel. You also can find QDR (40Gbps) cards out now that only are $1000 (and that's for a dual-port card, too). The Infiniband switches aren't any more than 10GbE per port.