Despite their high-level responsibilities and relatively lofty titles, CIOs and IT directors, no matter how large and prestigious the companies they serve, are not primarily interested in getting the glory. They are interested in a smoothly operating IT infrastructure - particularly when it comes to storage resources. In fact, they dream (during brief periods of insomnia-free nights, that is) of end users getting all the data they need when they need it. They envision SANs (storage area networks) that provide optimal utilization. They also want SANs to scale with ease and basically manage themselves. When those things consistently happen during actual waking hours, CIOs and IT directors love to give credit where credit should be due - not to people, but to products. As large in spirit as they are in vision, they especially love to praise "team player" products that don't complain about having to work with other products. Having paid (or convinced someone to pay) for various storage components, IT decision-makers dream of 100% interoperability.
Fortunately, standards groups such as the Storage Networking Industry Association (SNIA) are working diligently to make product-to-product interoperability a reality. The fact that these groups are primarily made up of vendor representatives means that storage vendors themselves are, for the most part, also committed to resolving product incompatibility issues. These efforts are key because interoperability is itself the key to anxiety-free SAN adoption and, consequently, hassle-free SAN management.
SANs Hit The SME Market
Interoperability efforts are particularly important now that small to medium enterprises (SMEs) are increasingly considering the move from direct-attached to SAN-based storage. Even more than their large enterprise counterparts, SMEs want SAN management to be, well, manageable. They understand that storage networking is complex; however, they don't want that complexity to result in increased IT staffing or decreased systems performance. Doug Rainbolt, VP of McDATA Corp.'s (Broomfield, CO) switch products group, acknowledges that SAN deployments are beginning to reflect smaller companies' needs. "In terms of port counts, we're seeing fabrics that aren't huge," Rainbolt says. "The trend is to sell small SANs with networking tools and switches included. Smaller companies want a SAN that is simple to manage and simple to scale."
Rainbolt's comments suggest the onset of widespread SAN adoption, a phenomenon that would have been difficult to imagine even a few short years ago. According to Wayne Rickard, chair of the technical council for SNIA, the concept of storage networking is relatively new. "Storage networking didn't exist in any sophisticated way five years ago," Rickard says. "Today, it's becoming the mainstream way to connect storage." However, mainstream adoption doesn't necessarily mean that the "mainstream," or SME market, will find SANs easy to implement. Says Rickard, "Now that you can buy servers from one vendor and storage devices from another, the good news is that you have choice. But, the bad news is also that you have choice. Storage is not yet as tightly integrated as it was when vendors hid it behind their own servers. So, initially, the price you will pay for potential flexibility, scalability, and manageability is incompatibility."
Interoperability - Not A Pipe Dream
All is not lost, however - even in the short term. In one fundamental aspect of current SAN deployments - Fibre Channel connectivity - interoperability is soon to become a non-issue, if it hasn't already. The T11 committee of NCITS (National Committee For Information Technology Standards), the Fibre Channel Industry Association (FCIA), and SNIA have all worked to refine basic Fibre Channel standards. Steve Wilson, chair of SNIA's Fibre Channel Working Committee, says these efforts demonstrate the maturity of the storage industry in terms of the willingness of all stakeholders to tackle interoperability issues. "Consider, for example, the SANmark test suite developed out of FCIA. All of the major players are participating. The SANmark testing standards deal with all aspects of port and fabric operation," Wilson says. "Another example is the Fibre Channel HBA (host bus adapter) API (application programming interface) developed within SNIA and transferred to T11 for documentation. That API enables a storage management application to discover attributes of HBAs and to obtain additional information about the SAN."
Despite the successes in achieving fabric-level compatibility, Wilson insists that interoperability must inevitably move closer to the management applications. "Switch to switch interoperability is important, but interoperability is increasingly important at higher device levels. Actually, from a management perspective, we want to get away from APIs at the switch and HBA level," he admits. "End users want an open management layer that sits on top of the fabric and enables higher level functions like distributing incident reports and zoning."
Applications Will Rule Storage
Mike Koclanes, CTO and cofounder of storage management software developer CreekPath Systems (Longmont, CO), agrees that the next interoperability push should occur at the software application level. As he sees it, today's storage networks respond to requests from applications more often than they do from servers or desktops. "The plumbing [i.e. interconnect] issues are gone, but the management issues are not," Koclanes says. "The trend is for storage management to step out from being device-oriented and, instead, approach the challenge of managing storage pools from the perspective of business applications." However, according to Koclanes, device-specific software from hardware vendors still tends to get in the way of application-oriented storage management tools. "It's true that you can have multivendor arrays, switches, and core directors on the same network," he says. "But, even if these things can sort of play together, the software tools often don't. Each device tends to have its own management tools and its own API."
Even though Koclanes believes that groups like SNIA are making great strides, he admits that it's unclear whether or not vendors will cooperate in creating common APIs. Nevertheless, he is convinced that storage management software developers can make the goal of establishing common device APIs irrelevant. "Software management tools can hide all of that," he says. "It won't matter to the end user if there are several APIs still sitting underneath." Rickard agrees, pointing to virtualization techniques that will eliminate the need to rewrite applications or driver-level code to support new storage devices: "With virtualization, file systems and applications at the top can have a consistent view of the storage underneath. At the same time, from the bottom up, arrays and peripherals can be isolated from the quirks of, for example, a particular version of UNIX or an oddly structured file system."
IP - The Bridge To SAN Islands
As companies get comfortable managing their storage in a SAN environment, the next step for many will be to scale up by connecting multiple SANs. In some scenarios, they will be supplementing Fibre Channel connectivity with IP (Internet protocol)-based technologies. "The enterprise market is now concerned with consolidating different SAN islands," says Rainbolt. "iSCSI (Internet small computer system interface) integrated with a Fibre Channel backbone is being locally deployed to incorporate low-end disk storage. FC/IP (Fibre Channel over IP) can be used for bridging between SANs at different sites." For Koclanes, the vision of the near future is the same. "It's inevitable that IP will play a role in storage," he says. "However, Fibre Channel will coexist with it for a long time."