Update Over at TechRepublic, Scott Lowe offers another view of AoE here. If I were an SMB VAR, I’d be checking AoE out.
It Is About Time
Here’s a potential game-changer – especially for the SMB market. It is low-cost SAN functionality based on local Ethernet. From a company named Coraid. Available for Windows, Linux, Solaris, FreeBSD and Mac OS X.
Wait a minute? Isn’t that iSCSI? It is a block device after all. Nope. Different. IMHO, better. There are some Don’t Gets, and a lot of Don’t Needs.
Putting Local – And Storage – Back In LAN
Coraid’s innovation is the open ATA over Ethernet (AoE) protocol. The big Don’t Get is that the protocol isn’t routable – it is strictly local – no IP involved. So the Don’t Needs include no TCP/IP overhead, no TCP/IP offload engines, no CPU-cycle sucking and latency-inducing TCP/IP stacks. AoE sits right on the data link layer – level two – of the ISO network model, so with a switched LAN – is there any other kind these days? – you get very low latency and full network bandwidth across a low-cost, industry standard LAN.
The other big Don’t Get: expensive and finicky Fibre Channel HBAs, switches and storage, along with the extra bandwidth FC offers. Like FC, AoE appears to make very effective use of available bandwidth – maxing it out with storage traffic. You’ll want a dedicated storage network to run AoE across.
Practice Makes Perfect
Even though it is cleared for use with Oracle, it probably isn’t a solution, today, for habitually late adopters. You’ll need to think through your security and system management processes to ensure that data doesn’t get munged by an inattentive sysadmin. A dedicated AoE SAN is a start, and VLAN techniques can help partition off potential damage-doers. The key: it just looks like a disk, and anything goofy you can do to a disk you can do over AoE.
Write Once, Read Never?
So far it appears that Coraid is the only company building AoE hardware. It doesn’t appear they are trying to keep anyone else from doing it, only it just hasn’t happened yet. That might be a worry for some folks. So in a smart move, Coraid has a Linux tool called srcat a tool for recovering data from the raw disks on a Coraid JBOD or array. So if the company goes belly up, controller breaks, no replacements available, you can still pull the drives and use srcat to pull the data off. Neat.
Congrats to Coraid for a creative way to bring the benefits of network economics to storage networks, just as some of us thought FC would 10 years ago. By creating an open platform and protocol, they’ve started the open-source equivalent of a SAN. If you require – or would like to be able to afford – a lot of storage capacity, you should certainly check these guys out.
Update: Over at Tech Republic, Scott Lowe offers some more info on AoE. The (literal) money quote:
AoE is cheap! An array capable of supporting up to 11.25 TB from Coraid starts at less than $4,000 without disks. Today’s price for a 750-GB disk at NewEgg.com is $400 and the unit supports 15 disks. So, for less than 10 grand, you can get 11.25 TB of shared block storage. If you do the math, that runs at about $888/TB or $0.87/GB. Not bad!