In Part 1 of this Storage Focus series on IP SANs, we discussed how with iSCSI recently gaining the IETF's seal of approval, some industry experts are predicting many startups and large storage vendors will redouble their efforts to develop storage arrays, host bus adapters, TCP offload accelerator cards, and management software products that support the standard. Let's continue our look at IP-based SANs and resume the debate over whether Fibre Channel (FC) SANs or IP SANs will ultimately prevail over the other.
It has been said that two of the major benefits of IP-based SANs (versus FC-based SANs) are gains in operational efficiency and reduced hardware component pricing. And even though there are still some that may disagree, many industry experts feel that IP-based storage solutions cover a wide range of markets, with a sweet spot potentially in mid-range applications.
There are also those who say that organizations should not be thinking about IP-based storage as an overall storage solution. But the main concern of IT departments remains whether or not the technology can be beneficial, and if so, what types of organizations will gain the most from using it?
Diamond Lauffin, senior executive vice president with Nexsan, says it's difficult to pinpoint what type of organization would benefit the most form this technology; however, he does feel that data center environments in which Fibre is not already installed and there isn’t a budget to install Fibre Channel would most likely find IP-based SANs to be an attractive option.
“IP-based storage is clearly going to take a position and is going to answer the needs of many organizations,” says Lauffin. These organizations would consist of companies that need flexibility in areas where they would not consider putting in a Fibre SAN for a variety of reasons, even if the cost differential came down.
For example, Lauffin says if a company has an existing Ethernet network that can support the current IP-based solutions and eventually 10-Gig E, there would be a great deal of attractiveness in deploying an IP solution as opposed to going through FC – especially at a departmental level and at a branch level. “This is where I see a significant level of interest and deployment,” says Lauffin.
Mid-Range Apps Better Suited for iSCSI?
Shaul Gal-Oz, CEO at SUNRAD, has found that mid-range applications are better suited for iSCSI. “Some lower-end customers (and small departments with low performance requirements) can still use NAS, while higher-end applications such as rendering, OLTP, and scientific simulations continue to use FC.” However, file servers, Web servers, messaging/email servers, data streaming systems, imaging systems, mid-range video streaming, print servers, etc. will operate very well within an IP-based SAN environment, says Gal-Oz.
IP-based storage products are becoming increasingly important components of the modern storage networking world. In Camp 1 are those who feel that because IP-based storage products comprise switches, routers, complex protocols, and traverse wide areas, the technology will inevitably suffer from latency, jitter, lost packets, and other common networking ailments. On the other side of the fence are those in Camp 2 – these are the folks who believe that the above are simply quality of service issues and that the application requirements for performance are of more importance.
“First off,” says Gal-Oz, “iSCSI is designed to deal with lost packets and slow performance within poorly designed solutions, and the session layer addresses these issues.” For example, he says, “we can back up and recover a server to and from storage that is located in another state or even another country,” although he did admit that this would obviously be slow if the user elected to perform this task over the Internet.
But he says the important thing about all of this is that it works, and his company has done it. SUNRAD has also successfully conducted data migration and replication over a line-of-sight infrared connection between buildings three miles apart and has built wireless SANs. Gal-Oz advises any IT department considering an IP-based SAN environment to work with an iSCSI product supplier that not only understands storage, but that is also extremely competent in TCP/IP networking.
As with any given technology, early on there are bugs, and over time those bugs are worked out and significant improvements are made. IP SANs are no different. Lauffin believes the majority of the issues that people speak about today concerning IP-based networks have all but gone away. “There are safeguards in place in the better IP systems, and these systems eliminate those concerns,” he says.