iSCSI Offload

The adapters are capable of performing full offload as both Initiatior and Target at 1, 10 and 40Gbps.

Just as computing power moved to decentralized networks of computers, storage technology has also evolved from host-centric direct-attached storage to network-centric Storage Area Networks (SANs). One of the great challenges facing the storage industry has been to provide reliable and manageable service over a network of inexpensive storage systems.

Fibre Channel (FC) vs. iSCSI

In today’s SANs, FC — featuring high bandwidth, low latency and advanced flow control for burst storage transfers — is the most popular method for connecting storage devices to networked clients. It does have some drawbacks, including:

• Requires a dedicated network to connect computing and storage nodes.
• Requires dedicated professionals to manage the network.
• Much smaller than Ethernet market and a small talent pool of qualified professionals available.
• Low volume (especially compared to Ethernet) translates into higher per-port costs.

Each of these disadvantages ultimately adds to the excessive total cost of ownership. To overcome the problems, the storage industry recently developed iSCSI, a new technology which allows a storage network to be built based on the popular TCP/IP protocol and Ethernet. The technology features the following benefits:

• Standards-based: iSCSI has been standardized by the Internet Engineering Task Force (IETF), enabling all vendors to build products to the same specifications. There have been a number of interoperability test labs established to ensure vendors’ products can communicate with one another.
• Ethernet-based: iSCSI can run on (but not limited to) the well-known Ethernet standard — the most widely deployed networking technology in the world. Unlike FC, there is a huge talent pool that knows how to build and manage Ethernet networks. And, because of its high volume, Ethernet per-port costs are unbelievably low — so low that virtually any organization or business can afford it.
• LAN / SAN Convergence: With the birth of iSCSI, local-area and storage-area networks can, for the first time, be merged using the same Ethernet technology. Since, both can run over the same network, managed by the same administrators, iSCSI helps significantly reduce total costs of ownership — far less than FC.

With the introduction and standardization of iSCSI, Ethernet has become a viable connectivity that development, combined with the 10 GbE and now 40GbE with offload capabilities, overcomes the traditional objections about Ethernet-based storage networks: low bandwidth, high latency, and lack of flow control.

Chelsio has taken a leading role in this market segment with the introduction of the Terminator Series Converged Network Adapters (CNAs). The family of adapters stands out as the leading storage networking building block, thanks to its record throughput and IOPS, as well as its Ethernet-based technology. These adapters have greater throughput and lower latency than competing technologies, and is driving the convergence of LANs, SANs and NAS by supporting multiple protocols. With the Chelsio Terminator Series, 40,10 and 1GbE iSCSI offload is real and available.