The storage network for the rest of us
A 6 year old storage company you've never heard of got a $25 million VC injection last week. That's big money. The promise: the lowest-cost and highest performance storage network in the world. Is this the storage network for the rest of us?
It's a too common story in high tech: great technology; clueless marketing; no traction. I wrote about Coraid 4 years ago because I liked what I saw: a simple, low-cost, high-performance Ethernet-based storage network based on an open protocol.
Coraid's innovation is the open ATA over Ethernet (AoE) protocol. 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? - you get very low latency and full network bandwidth across a low-cost, industry standard LAN.
That's pretty cool with gigabit Ethernet, but think on this: by late next year motherboard 10 GigE ports @$50/ea will be standard - with 10 gig switch prices following. One port for LAN; one port for SAN. At a gigabyte per second.
The protocol isn't routable - but Coraid has a WAN gateway for those who have the need - no IP involved. So there's no TCP/IP overhead, no TCP/IP offload engines, no CPU-cycle sucking and latency-inducing TCP/IP stacks.
Compared to Fibre Channel There is no comparison: no expensive and finicky Fibre Channel HBAs, switches and storage. Like FC, AoE makes effective use of available bandwidth - maxing it out with storage traffic. You'll want a dedicated storage network to run AoE.
Coraid's market isn't today's FC shops. It's the folks who could benefit from unified block storage but haven't been able to afford it.
Compared to iSCSI iSCSI sits atop the IP and TCP layers. You have to deal with IP configuration. AoE auto-discovers disks and LUNs. Much simpler.
Because it's ATA - as in SATA and PATA - the drives appear to the system as internal SATA drives. They can be partitioned or formatted like any local drive in Windows, Linux or Mac.
AoE array LUNs can be striped for capacity or bandwidth - though 10 GigE is needed for the latter. In short, this is flexible and low-cost storage that you already know how to manage.
Update: Jim Kemp of Coraid wrote to say that they now have an ESX driver and HBA that presents an iSCSI device that supports VMware's VMFS cluster filesystem. Software-only drivers may not support the SCSI functionality. I thank Jim for the update and regret the error. End update.
The Storage Bits take As the product manager for the first full Fibre Channel array, I know that FC and storage networks have fallen far short of the hopes we had for them in the late 90s. Interoperability was often promised but never delivered in production environments.
As a result, the hoped-for network effects of lower costs, higher scale and greater performance were never realized. AoE may change that.
"Ethernet wins" is a Silicon Valley truism. Now that we have a funded player pushing it, we may finally see that extended to storage networks.
Comments welcome, of course. I have no business dealings with Coraid.