Clearing up some misconceptions about the AoE protocol

I have stumbled upon an interesting blog conversation regarding the AoE protocol, a cornerstone of the Coraid Etherdrive storage systems we recommend. I have come across many storage professionals who just don’t seem to like simplicity in anything and AoE is so simple it does take a lot of convincing for some to take it seriously – this is no exception! The blog to which I am referring to was entitled “ATA over Ethernet for converged data center networks? No way” and originally published here. Many points were raised but were picked up by Coraid and the response makes some interesting reading, not only for the way in which the points raised were dealt with, but also in the way it shows just how far we still need to go to convince some storage professionals that you can have simple in an Enterprise! The response in its entirety appears below:   No sequencing The protocol does not contain a single sequence number that would allow servers and storage arrays to differentiate between requests or split a single request into multiple Ethernet frames. A server can thus have only a single outstanding request with any particular storage array. (Or maybe LUN — who knows? The protocol specifications are silent.) Answer: As packets between initiator and target are not connection based, sequence numbers are irrelevant. A client can, however, have multiple requests outstanding with different tag values which is how a target differentiates between requests. Spreading between Ethernet frames is performed by the client who is responsible for turning a large request into a series of MTU sized requests (a 64KB...