Storage Tip: iSCSI is doing just fine thank you

April 26, 2007 —

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What seems to be the problem? One of the things that, as an analyst, I tend to forget is that not everyone is familiar with storage technologies even though they have been around for awhile and talked about extensively in the media. So it is with iSCSI. You may or may not be familiar with iSCSI, but you should know about the future of iSCSI -- especially in relationship to the other major storage networking protocol -- Fibre Channel.

What do you need to know? iSCSI is a networking protocol that allows the use of familiar SCSI-based I/O over TCP/IP networks. The fact that Ethernet is ubiquitous for all sizes of organizations leads to some of the perceived major advantages of iSCSI as the protocol for a SAN instead of Fibre Channel. Those advantages are that existing personnel do not have to undergo major retraining (which would be necessary with a Fibre Channel SAN), lower cost, and greater simplicity in deployment and maintenance.

iSCSI has a lot of other things going for it as well. iSCSI works well over a WAN therefore remote backup using electronic vaulting to a remote disaster recovery site is quite feasible. Server virtualization combined with SAN virtualization is receiving a lot of attention. Leading server virtualization vendor VMware supports iSCSI. Microsoft has thrown its weight behind iSCSI. So what's not to like.

Well, Fibre Channel advocates would throw out the fact that Fibre Channel SANs have higher performance. That is true enough, but for most proposed iSCSI implementations, performance is good enough to do the job. And even though its adoption is likely to proceed cautiously, 10GbE (10 gigabit Ethernet) will eliminate any advantages. In the long run, Ethernet wins any performance battle.

The reason Fibre Channel SANs will survive for the foreseeable future is proven robustness and reliability in mission-critical and business critical environments. That does not mean that iSCSI has not matured enough. iSCSI is now considered as capable enough for production environments with little risk. However, no matter how little the risk, any switching cost risks are too much to take a chance in an enterprise-class data center environment.

That does not mean that Fibre Channel will prosper; revenue growth projections for the next few years are about at the rate of inflation. In contrast, iSCSI is forecasted by IDC to grow in the high two digits annually in revenues and in triple digits in terms of storage supported by iSCSI. Since iSCSI started from a smaller base, iSCSI is not projected to catch up with Fibre Channel in the next four years or so. However, the growth in dollars for iSCSI each year is likely to be greater than for Fibre Channel so iSCSI vendors are likely to continue doing very well.

What can you do about it? The iSCSI market has matured nicely and a number of vendors have demonstrated their success in delivering iSCSI products and services. Any level company from SMB to enterprise should feel comfortable in adopting iSCSI where appropriate. And where appropriate is likely to be for whatever applications Fibre Channel had not already been adopted and for which storage networking may provide some advantages. That could be where DAS has continued to be used because a SAN was perceived as too expensive. But it could also be for new applications, such as video surveillance or remote office data protection. So iSCSI will prosper in applications for which Fibre Channel was considered too expensive or overkill. However, iSCSI may very well prove to be the proverbial nose in the camel's tent as it takes on more responsibility for critical production applications as time goes on as well.

storage.itworld.com