I have been researching storage for the past few days. I've been concentrating on iSCSI, since I was trying to keep costs down, and a fiber switch is pretty expensive (especially if I want to use it).
While researching, I chanced upon a technology I hadn't heard before: ATA Over Ethernet (AoE). Unlike iSCSI, which transmits the data over TCP, AoE does it via layer 2 frames. This has the implication that, like Fibre Channel, it can't be routed across different networks. For most people, this is not a problem. For some, it's a deal breaker.
In the same way that iSCSI can use software initiators (which turn a computer into an "iscsi server"), there is software available to create AoE "servers". This would be useful if you've got a large machine with many available disk slots.
There are also AoE arrays on the market. Coraid sells some very large arrays. They even offer a ready-made High Availability NAS gateway.
There are drawbacks, of course. There doesn't appear to be a lot (any?) inherent security in the protocol. If anyone reading has experience, I'd be very thankful for some comments as to how host control is done.
I've read comments that were a few years old claiming that it wasn't as stable as iSCSI, but they offered no evidence towards that conclusion, so I have no way of checking to see if their complaints have been resolved.
In the end, I still don't know what I will do, but the more I read, the bigger a blip it is becoming on my radar. What do you think?