Storage-area networks may see lift from IP-based high-bandwidth connection
Ask most information technology managers about data growth in their organizations, and their answers are likely to contain the word "inevitable." Like death and taxes, the growth of digital data has become another certainty, with analysts reporting that rates of data growth are approaching 70 percent to 100 percent per year in many organizations.
The issue of what to do with all that data has driven the creation of new storage tools beyond the confines of an individual disk or disk array. The storage-area network (SAN) is one type of networked storage solution intended to cope with the growing flood of data.
But, up to now, real SANs that is, heterogeneous storage platforms in a highly manageable network used to create a "utility infrastructure" have remained elusive. In the late 1990s, SAN-like solutions were introduced that used as their plumbing a less-than- ideal serial storage interconnect protocol called Fibre Channel.
The problem was that the IBM Corp. designers who created Fibre Channel excluded key features, such as support for mixed storage platforms and sophisticated management and security functions, because they sought to avoid overhead cost and preserve the maximum bandwidth of the server/storage interconnect for SCSI commands and data.
Now, an alternative to Fibre Channel is trickling into the market. It's based on ubiquitous IP standards, which include provisions for management and security. Although most storage vendors have announced plans to offer products using the new SCSI over IP or iSCSI standard, the protocol is still not complete. The current dearth of products makes it difficult to assess the full impact iSCSI will have, but most industry insiders expect it to be big.
The initial reference specification for iSCSI was submitted to the Internet Engineering Task Force in November 2000, and since then, it has been the subject of an intense debate. The IP Storage Working Group has missed at least two target dates for the release of a final version, along with a request for comment (RFC). Developers now claim that the final version of the protocol will arrive this summer.
The absence of an RFC has not stopped major vendors from announcing iSCSI products. Both Cisco Systems Inc., with partner Adaptec Corp., and Hitachi Data Systems, with partners Alacritech Inc. and Nishan Systems, announced in January that they would have iSCSI SANs ready for sale before the end of the year.
Releases of prestandard iSCSI products by companies such as Emulex Corp. and IBM have met with lukewarm reception from commercial and government organizations.
Although it would seem inevitable for Ethernet and IP networks to "gobble up everything in sight, including storage, there is little customer mandate for iSCSI per se," according to Steve Krauss, business development manager on the storage solutions technology team at GTSI Corp.
Most federal government customers lack the resources to keep up with storage technology protocols, according to Krauss.
"The world of storage is complex and confusing, and customers are application-focused," he said. "They know they are having problems with the business, not that they need a Fibre Channel SAN or an iSCSI SAN."
This is why they often turn to systems integrators to prescribe solutions, he added.
However, the products that integrators have to choose from are mostly Fibre Channel, not iSCSI, said Gareth Taube, senior vice president for IP storage networking at Emulex, which has started shipping a new host bus adapter based on the prestandard iSCSI.
One reason that efforts to excite federal consumers about iSCSI SANs are lagging is due to the lack of target devices storage devices and other enabling equipment for use in demonstrating capabilities such as improved manageability, Taube said.
"IP gives an advantage over Fibre Channel in terms of management," Taube said. "You can use the same interconnect to see how data is doing on a storage device or data segment using in-band network management. That's something you can't do [with Fibre Channel], and it is required to establish a professional-quality storage environment."
Bob Rodgers, chief storage technologist with BMC Software Inc., agreed that management is crucial to storage cost containment, but he is not convinced that access to a Simple Network Management Protocol (SNMP) service provides sufficient motivation for customers to embrace iSCSI SANs.
"SNMP has been out for years and years my guess is that 80 [percent] to 85 percent of storage platforms are instrumented for management via SNMP," Rodgers said. "But larger organizations, including government organizations, are reluctant to use SNMP management with their storage. The perception is that SNMP represents a security threat."
SNMP-based management, he said, potentially gives hackers and other unauthorized people access to device-configuration tools, which they can use to gain access to the IP network. The potential data loss and downtime resulting from misuse of management tools have had a chilling effect on iSCSI's market popularity.
Also not helping the situation is confusion about the proper fit for iSCSI in storage architecture. Is it a replacement for Fibre Channel or does it complement existing Fibre Channel deployments? Vendors' messages are often a mix of conflicting and self-serving generalizations.
Emulex's Taube believes that iSCSI SANs will eventually displace Fibre Channel SANs, despite any current inhibitors. "Ethernet is familiar technology, so the technical absorption of iSCSI SANs will be much faster than Fibre Channel," he said. "It is based on technology you already know, Ethernet and IP networks, and your staff is already trained to deploy it. This results in a lower total cost of ownership that will drive adoption."
He also shares the view that iSCSI SANs will be maintained in a separate IP network, away from the "messaging network" or the local-area network already deployed by the organization. Different performance management issues dictate as much, because iSCSI uses a larger packet size than most messaging networks, Taube said.
Not everyone agrees with the view of iSCSI as a replacement for Fibre Channel in a SAN. According to Fibre Channel switch maker Brocade Communications Corp., iSCSI's role is that of a bridge between a Fibre Channel SAN located in an organization's data center and outlying servers that are less critical.
"Getting through the hype around iSCSI, it has only a few clear benefits," said Camden Ford, senior product marketing manager at Brocade Communications. "ISCSI should be used to extend host access to an existing Fibre Channel SAN infrastructure when that strategy is less expensive than pulling Fibre Channel out to the remote server."
This view flies in the face of storage strategies from leading technology companies such as Microsoft Corp., according to Rich Lautzenheiser, vice president of marketing and business development for Crossroads Systems Inc.
Lautzenheiser, whose company makes a "protocol-agnostic" storage router, said that Microsoft's decentralized computing architecture will likely be reflected in its evolving enterprise storage strategy. In a decentralized setting, IP-based SANs will likely thrive.
Omar Barraza, director of product management for Dot Hill Systems Corp., agreed.
"Microsoft's computing model consists of a distributed network of small servers," Barraza said. "It would be cost-prohibitive to connect these distributed server platforms to a Fibre Channel SAN. And at the network server level, smaller blade servers don't have space for additional [host bus adapters]. IP connectivity is the only option available."
Both Lautzenheiser and Barraza also concur that it is too early to see strong adoption of iSCSI within the federal government, where both companies have many customers. "The storage industry has a fascination for migration to the latest and greatest technology," Barraza said. "I doubt that anyone will be rushing to adopt iSCSI for the sake of iSCSI itself."
Richard Garifo, vice president of enterprise technology for the computing systems business unit of Northrop Grumman Information Technology, echoes this. "If we are seeing any interest at all, it is coming from high-end technology consumers," Garifo said. "They are keeping abreast of the technology, but there are no pilots yet and no implementations that I am aware of. The interest is strictly at the laboratory level."
Toigo is an independent consultant and author specializing in business automation issues. He can be reached via his Web site at www.toigoproductions.com.
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