Once the Gigabit Ethernet standard was announced in the late 1990's, it became clear to the CORAID co-founder, who is also the inventor of the Cisco PIX firewall, a new alternative may exist for network storage without the high costs and limiting factors of Fibre Channel and iSCSI. A goal of making high performance network storage that is also affordable became a reality with the open network protocol designated AoE, short for ATA-over-Ethernet. AoE was pioneered by CORAID and is supported by Linux and is available as part of all major Linux distributions. CORAID's AoE is a competing technology to Fibre Channel and iSCSI. AoE is freely available to anyone. CORAID EtherDrive storage appliances, all based on AoE, are available at a fraction of the cost of comparable storage products and solutions, thus enabling VMware ESX customers a needed option for network storage which is high performance and very affordable.
When the decision was made to use Ethernet to enable network storage, it quickly became apparent that the true speeds of Ethernet had to be fully realized and could not be by using TCP/IP. In networking there are several layers to consider when designing a network protocol, starting with the physical layer, the fastest, all the way to the software driver or application layer. These layers too often depend on generic handling of networking details at lower layers causing too much overhead and processing, thus resulting in much slower speeds and performance as a result. Unfortunately TCP/IP fits this slow case when trying to enjoy the speeds available with Gigabit Ethernet. Therefore the design goal became clear; develop the network protocol as close to the hardware layer as possible, yet have it be manageable enough so as not to be tied to one piece of Ethernet hardware. Ethernet datagrams fit this design goal and became the cornerstone of the yet unnamed protocol. As it happens, using only datagrams for a protocol, translates into enormous scaling and performance benefits when the protocol is developed in a pure, clean manner.
Keeping in mind the design goal of maximum Ethernet speed, it became imperative to have the proper, efficient message structure and commands to make Ethernet based network storage a reality. Embedding ATA commands into the Ethernet datagrams fit this design goal exceedingly well. The ATA commands completed the protocol, aptly named "ATA-over-Ethernet", or AoE. It is important to note that because AoE is a true protocol, it does not matter what type of hard drive is used when implementing the protocol and corresponding driver. CORAID develops its EtherDrive storage appliances for the most affordable and reliable hard drives on the market to benefit users controlling costs while providing ease of storage growth and management.
For information on CORAID EtherDrive SAN visit www.coraid.com