Mashing up Fibre Channel, iSCSI

Arthur Cole

For enterprises that have already deployed Fibre Channel SANs, the question of the moment is not whether iSCSI or Fibre Channel is the superior technology. Rather, the real dilemma is trying to get the two protocols to work together as a seamless storage environment.


There are many good reasons to launch iSCSI in a Fibre Channel environment, cost and flexibility among them. But there are a number of considerations to take in when planning an integrated environment, according to blogger Steve Bigelow. Among them is the fact that FC does not always outperform iSCSI, particularly with applications that don't require a lot of bandwidth -- and if you have the foresight to deploy specialized iSCSI NICs using TOE (TCP/IP Offload Engine) technology.


iSCSI/Fibre Channel integration is also being helped along by the Fibre Channel over Ethernet (FCoE) standard backed by Brocade, Cisco, Emulex, QLogic and others. One of the chief advantages here is that FCoE maps the SCSI protocol directly to the Ethernet -- something not even iSCSI can do -- which means you can still use your existing Fibre Channel management applications to manage your SAN.


The biggest drawback to FCoE, however, is the fact that it is not routable, due to the absence of a TCP/IP component. That means it's largely restricted to the LAN. For wider use, you'll need a Fibre Channel over IP device, currently under development at Brocade and Cisco.


What's most interesting about FCoE is that many pundits have long been predicting the end of Fibre Channel in the face of low-cost competition from iSCSI. But now that an all-Ethernet SAN is within the realm of possibility, it could be iSCSI that has a tough time competing on a level playing field. In the meantime, however, there are still plenty of environments that land themselves to a mixture of both.

Add Comment      Leave a comment on this blog post
Nov 16, 2007 12:01 PM Michele Sinclair Michele Sinclair  says:
This is a great article on FC vs. iSCSI, but did you know that MPC Computers has a SAN device (DF-2112) that uses FalconStor technology and you can actually view your other SAN environments from this s/w, while managing the SAN environment?It is a brand new iSCSI SAN solution that MPC is currently offering as an option. Check it out! It would be interesting to see how their SAN solution compares to others, since it is utilizing s/w technology that is readily available to Fortune 1000 companies. Reply
Dec 10, 2007 7:14 AM Dave DuPont Dave DuPont  says:
Intelligent network switches, unlike other iSCSI solutions, can put the power of iSCSI and virtualization directly between physical storage devices and the network. By doing so, they avoid the redundancy and other limitations of integrated iSCSI storage arrays. This enables organizations to quickly and easily deploy iSCSI and to unlock the value of storage virtualization while still leveraging existing investments in Fibre Channel.Because intelligent network switches are device-agnostic, customers have the flexibility to choose the storage hardware they prefer whether they are retaining current storage devices or purchasing new ones. Customers can continue to leverage their investments in existing storage hardware, or choose new arrays that precisely match specific applications, all without being locked into proprietary devices or technology.The Dell/EqualLogic acquisition underscores the benefits of iSCSI. However, this Dell move is targeted predominantly at SMBs which typically dont have significant storage infrastructures. Larger enterprises have existing storage investments and more demanding IT requirements where the intelligent switch approach often offers the best solution. One should not discount the continued use and proliferation of enterprise Fibre Channel SAN solutions. Intelligent network switches work seamlessly with a mixed iSCSI/Fibre Channel enterprise by connecting these traditionally disparate storage solutions into a complete virtualized storage infrastructure. So, while the Dell/EqualLogic combination continues to drive increased attention to iSCSI implementations, it should also be noted that storage-centric solutions are not the only market alternative. Intelligent network switches play an important complementary role as companies add a growing number of iSCSI storage arrays to their storage infrastructure mix. Reply

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