Resolve the war between FCoE and iSCSI network protocols (3)

FCoE vs iSCSI

After discussing the fusion mode, we can finally talk about whether to choose iSCSI or FCoE. The following are four main considerations: 1. Data center strategy, 2. Performance Requirements, 3. Compatibility goals, 4. Cost issues. In any situation, these four factors are very important for selecting FCoE or iSCSI, and the final decision can be made without any factors. In some cases, FCoE may be cheaper than iSCSI, and vice versa.

Figure 6 multi-faceted SCSI

No matter which protocol is selected, one element remains unchanged, that is, SCSI. Almost all enterprise-level block storage protocols are based on SCSI. It is one of the pioneering technologies of enterprise-level storage, each enterprise-level Block Storage protocol, including FCoE, iSCSI, SAS, and FC protocols, is transmitted through SCSI. This makes the protocol selection have little to do with the operating system and applications, because the "View" storage methods are the same. The biggest difference between the three SAN protocols is that the Routing Capability, availability of hosts, startup hardware and software, and maturity and availability of management tools.

Figure 7 Protocol Comparison

ISCSI has a more powerful support matrix than FCoE. Almost every operating system has corresponding hardware and software drivers, and almost every vendor provides mature storage systems to support it, the Greenfield SAN design without existing fiber channel infrastructure should have no development prospects. iSCSI is the ideal choice for new storage networks.

Figure 8 three fiber channel routes

On the other hand, FCoE is an evolution of the enterprise's fiber channel storage network. There are three ways to go before the fiber channel Architect: the first is to continue using end-to-end fiber channels, the second is Internet and edge FCoE, and the third is to build an end-to-end FCoE SAN. The last route was not possible until recently. It is also the most popular Fiber Channel architecture model and will eventually become the dominant one.

Figure 5 four factors for selecting a protocol

Future of iSCSI and FCoE

For organizations that have deployed a large number of Fiber Channel devices, FCoE is a gradual transition. These environments will gradually adopt Ethernet as the edge protocol, however, they will continue to use existing enterprise-level Fiber Channel storage arrays. Strategically, FCoE is more meaningful to users in the long term, but it still needs to further prove its capabilities, such as congestion notification and Ethernet Optical Fiber technology, which are not mature enough in terms of interoperability.

We often compare the efficiency of FCoE and iSCSI protocols. The efficiency of packaging SCSI in TCP/IP is not high, but the protocol analysis results show that FC, the absolute bit efficiency between FCE and iSCSI is very close. Dell Technical Center and other tests show that iSCSI is highly efficient in terms of data throughput and CPU utilization. FCoE and iSCSI are not mutually opposed. Your choice depends on many factors. iSCSI is a good choice if there is no fiber channel investment or a poor large-scale upgrade is required, FCoE may be used more in high-end enterprises.

In the absence of fiber channel investments or the need for poor large-scale upgrades, iSCSI is a good choice. Based on its ease of use, low cost, high performance, and extensive support, it will continue to grow, it is much easier to transition to 10 GB Ethernet. On the other hand, FCoE is likely to occupy the high-end enterprise market, and major manufacturers are actively promoting it. It seems that they will force the upgrade in the end, but the prime time in some fields is still not yet reached, and the purchaser's promise of the dike is exaggerated.

Some may ask why Ethernet is needed and there is still much work to be done to become the dominant protocol for convergence. Why not InfiniBand is it good in performance, interoperability and scalability, is it also widely used? Price is a factor, but the main factor is the foundation. There is no doubt that Ethernet will eventually overcome its own obstacles. Many protocols seem to be more suitable for integration, including ATM and even the licensing ring. Although the fiber channel based on the licensing ring sounds attractive, we still expect that FCoE and iSCSI will dominate the world.

For more information about the two network protocols FCoE and iSCSI, see:

Resolve the war between FCoE and iSCSI network protocols (1)

Parsing the war between the FCoE and iSCSI network protocols 2)