* Posts by BMac

1 publicly visible post • joined 5 Feb 2010

Bruce Almighty drives Coraid AoE plan after $10m investment

BMac
Thumb Down

SAN and LAN shouldn't mingle.

I'm not familiar with the EtherSCSI product so I won't address your comparison there, but I do think you made some interesting points about a layer2 storage protocol in general terms that should be discussed as I am familiar with the CORAID products.

AoE is indeed a layer 2 protocol which does means it is non-routable. Thus, communications are by definition contained within a network segment or VLAN. Typically, this network segment is called a SAN (Storage Area Network). In my experience, general best practices for a SAN would not include co-mingling traffic with the LAN (Local Area Network) so if one was concerned about a Storage protocol affecting the bandwidth for SMB traffic, I'd question your architecture.

AoE should be compared to typical storage protocols such as iSCSI or Fiber Channel. Rather than requiring the overhead of TCP\IP as a transport (like iSCSI) or requiring proprietary and expensive hardware for the SAN fabric (like Fiber Channel) it takes advantage a all many features of Ethernet such as multi-path awareness and the ability to "selfishly flood" an available link to increase performance. In fact, these features are why AoE can easily outperform iSCSI and are more comparable to FC speeds.

Raw Ethernet is a very effective transport medium, especially when using jumbo frames, and multiple paths in a switched environment (add another GigE link between initiator and target and AoE automatically saturates that link and increases performance). This could hardly be considered a fractional performance gain, IMHO...

USB 3.0 will be great for DAS... don't immediately see it replacing SAN storage protocols anytime soon.