* ATA over Ethernet
Increasing needs for storage have given rise to storage-area networks, with Fibre Channel and iSCSI among the most prominent technologies used. Another option is called ATA over Ethernet.
This week’s Technology Update is all about AoE and is written by Brantley Coile, founder and CTO of Coraid, and a co-author of the AoE protocol. While not an industry standard, Coraid says it is an open protocol and published the most recent version of the specification here in February.
Fibre Channel has long been called expensive. While iSCSI makes it possible to use inexpensive Ethernet gear, it also has been called complex to use because it introduces the overhead of TCP/IP, and sometimes means getting TCP offload engines to handle that processing.
AoE is intended to make it easy to take disk storage out of servers and put it out on a network so that it is more widely available and not tied to specific servers. It transports ATA disk commands over standard Ethernet without using TCP/IP, Coile writes in the Tech Update. He claims that its scalability is unlimited. AoE is a low-level protocol that’s much simpler than TCP/IP, and in a local environment, the complexity is often unneeded.
Supported by a Linux kernel driver, AoE allows communication between servers and networked ATA drives, and makes the remote drives look like any other local disks.
AoE storage devices can be single disks or groups arranged in RAID configurations, Coile writes. Overall, the emphasis is on low cost, simplicity and scalability, factors that become more important as even small businesses get into storing large files, such as those holding video or high-resolution images.
