Product assessments
Here's how the multiprotocol arrays from the various vendors stack up:

EMC. As the leading FC array vendor, EMC has the benefit of selling its Celerra multiprotocol NAS and gateways into its large customer base. With a feature set similar to that of NetApp, as well as the ability to complement its block-based arrays, EMC is a strong player in the combined NAS/SAN array market. Unlike NetApp, however, EMC doesn't enjoy the benefits of a unified array architecture; as a result, administration and management of the different array families varies.

"With Symmetrix, Clariion, Celerra and Centera, EMC has four different solutions, each with its own code base and architecture, and it would make sense for EMC to head to a unified solution," says Brian Garrett, technical director, ESG Lab at Enterprise Strategy Group (ESG), Milford, MA.

HDS. The FC array behemoth has put little in-house development into file-system protocols. With the exception of a NAS blade for its TagmaStore USP, HDS relies on its relationship with BlueArc Corp. for file-system protocol support, offering the Hitachi high-performance NAS platform (BlueArc NAS gateway) to customers who need file-system protocol support beyond the USP NAS blade.

HP. As a traditional block-based array vendor, HP has entered the NAS market with two offerings. At the high end it offers HP Scalable NAS, which is mostly NAS, although it supports iSCSI if used with an iSCSI-enabled array. For the SMB market, HP offers the HP StorageWorks AiO Storage System, which is available in different flavors depending on how much storage is required. Although AiO runs Microsoft Windows Storage Server, the addition of tools like Application Storage Manager and HP's superb support organization have made AiO one of the simplest multiprotocol arrays on the market.

IBM. The company, even more than HDS, has decided not to develop file-system protocol technologies in-house. Instead, IBM OEMs and sells NetApp filers and gateways to customers in need of NAS protocols.

Microsoft. The company entered the multiprotocol market by acquiring iSCSI target software from WinTarget in 2006, providing an iSCSI option for its Windows Storage Server NAS. With about 50 Windows Storage Server OEMs, including powerhouses like Dell Inc. and HP, Windows Storage Server has evolved into a formidable player in the multiprotocol array market. Although Microsoft has traditionally dominated the SMB market with Windows Unified Data Storage Server (WUDSS) 2003 and its out-of-the-box iSCSI support and clustering, it's now also competing in the enterprise space.

NetApp. The first array vendor to offer block- and file-based protocol support in its products, and it clearly leads the pack. Most importantly, among the leading array vendors, NetApp is the only one with a unified array architecture. From its low-end FAS200 to the high-end FAS6000, NetApp's arrays are all based on a single architecture and run the same software. A large number of features, combined with ease of use, make NetApp well positioned in the multiprotocol array market. "NetApp has always been easier and EMC has always been more complex," says Garrett.

Pillar Data Systems. A Larry Ellison-financed startup, Pillar has supported FC, iSCSI, NFS and CIFS in its Axiom arrays from day one. A scalable architecture, offloading of file-system protocol and RAID processing to so-called "Slammers," and cluster support make the Axiom array family a great fit for SMBs and enterprises. Tight integration with Oracle Corp. tools like Oracle Enterprise Manager makes Axiom arrays a perfect fit in Oracle environments. "By having separate data paths for iSCSI, FC and file-system protocols, Pillar has one of the best-performing multiprotocol arrays in the market," says Gartner's Cox.

The demand for arrays that support both NAS and SAN protocols is on the rise. The sweet spot for a multiprotocol array is an environment that needs the flexibility of file- and block-based protocols, and where features and ease of use are more important than very high performance. "Virtualization will drive multinetworked and multiprotocol solutions," says Garrett. "And [the vendor that] can achieve it in a simple, integrated, scalable and affordable fashion will be the big winner."