File-Area Networking Brings FAN Frenzy to Storage

By Drew Robb (Send Email)
Posted Aug 8, 2007


Fan trouble is sometimes associated with basketball in the United States, or football in the rest of the world. But the storage universe is in the midst of its own fan trouble — courtesy of one of its newest catch phrases, the File Area Network (FAN).

As each vendor spars for its own corner, file virtualization is fast becoming the latest storage battleground.

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"A FAN is defined as a way to improve management of unstructured data by decoupling that data from specific servers or NAS filers, and offering services such as data migration, load balancing, and replication," said Rick Gillett, CTO of Acopia Networks (Lowell, Mass.). "FAN is analogous to the changes that started during the 1990s when SANs became the popular means of improving management of block storage."

Known by some as file virtualization, FANs provide a way to aggregate file systems so they can be more easily moved and centrally managed. Gillett, who is also on the Storage Networking Industry Association's (SNIA's) FAN working group, does his best to be fair when discussing Acopia's competition. In a recent presentation at Storage Networking World, for example, he avoided mention of any specific vendor and attempted to discuss the technology as a whole.

Gillett laid out several styles of FAN: client-based, network-based and hybrid. The client-based systems operate out of band with the OS service or agent loaded on the client system. This approach provides granularity down to the tree level (as opposed to individual files) and functions only with specific NAS protocols.

"Client-based FANs don't require new hardware, but data access can be disrupted during such operations as migrations," said Gillett. "This approach does not support replication or load balancing."

Hybrid systems use a combination of client and network technologies. Although these systems experience far less data disruption, they also require new hardware, may have problems scaling, and decouple only down to tree-level, according to Gillett.

Some FAN Vendors
Acopia Networks (Lowell, Mass.)
Attune Systems (Santa Clara, Calif.)
Brocade Communications Systems (San Jose, Calif.)
EMC (Hopkinton, Mass.)
NeoPath (acquired by Cisco) (Mountain View, Calif.)
Network Appliance   (Sunnyvale, Calif.)

Get Gillett talking long enough in private, however, and he starts to spill the beans. His favored approach, and the one Acopia uses, is network-based. This in-band method enables continuous network-resident decoupling and file-level granularity, causes no data disruption, and operates across all NAS protocols. When asked about its downsides, he conceded that a network-based approach requires some hardware and may, in some cases, have difficulty scaling.

"Once you decouple the data, you facilitate the delivery of advanced services," said Gillett. "Nobody else supports advanced services like Acopia."

He's referring to functionality like load balancing, migration, replication, global namespace and the establishment of a "Tier 0" within a tiered storage infrastructure. This is a small area of memory reserved only for hot files earmarked for heavy usage.

X-Rated Storage

There are plenty of vendor choices within the various FAN categories. StorageX from Brocade Communications Systems (San Jose, Calif.), also marketed as NetApp Virtual File Manager (VFM) by Network Appliance (Sunnyvale, Calif.), is a client-based system for file virtualization, replication, disaster recovery/failover and migration. The global namespace in VFM, for example, makes it easier to manage file structures and move data. Files can be ported to any hardware using a global namespace. Should an emergency failover occur, users continue accessing data as if nothing happened. File system recovery is also accelerated.

Jay Kidd, NetApp's general manager of emerging products, points out that VFM delivers host-based file virtualization, while the company's DataOnTap GX file system deals with virtualizing the underlying storage subsystems.

"OnTap GX enables clustered storage, a unified namespace across multiple clusters and can scale up to 6 PB," says Kidd.

Brocade attempts to differentiate itself from its competitors by stressing that StorageX can fully integrate with Brocade WAFS (Wide Area File Services) to create a wide-ranging system for internal and external file virtualization (e.g., the FAN can be extended to cover remote offices).

"A FAN makes it easy to manage multiple file servers or NAS filers, as it offers one view of all files yet remains transparent to the end user," says Philippe Nicolas, technology evangelist for FAN solutions, "Brocade offers a unified interface to tie together Brocade WAFS with our StorageX FAN software."

EMC (Hopkinton, Mass.) meanwhile, offers several technologies that could loosely be defined as a FAN. Probably the best example is EMC Rainfinity Global File Virtualization. It virtualizes unstructured data environments and moves data (including active, open files) without disruption. In Gillett's classification above, it would be characterized as hybrid, as it operates in and out of band.

All of these vendors take a different tack when it comes to file virtualization. Attune Systems (Santa Clara, Calif.) is no exception. Attune's Maestro File Manager FM5500 appliance operates in band and creates a virtualization layer between file servers and clients or applications. As a result, content can be moved around seamlessly, and a shared storage pool can be created using servers and NAS boxes.

The company stresses that a FAN consists of four elements: discovery of the environment, policy management, non-disruptive migration and global namespace.

"Attune, Acopia and NeoPath (acquired by Cisco) are the only solutions that cover all four," says Daniel Liddle, vice president of marketing at Attune. "We are the only vendor that does all four elements for Windows-based systems."

Like most vendors, Liddle emphasized the upside of his own product, as well as a few shortcomings in the others. In his view, EMC Rainfinity mainly does non-disruptive migration, whereas Brocade is focused more on the namespace side of the equation. Neopath does Linux and Unix but not Windows, he said, so it is not considered a competitor to Acopia.

Acopia, said Liddle, mainly seeks customers from the Fortune 500, while Attune emphasizes the midmarket Windows segment. Like Acopia, Attune is in-band. However, it takes a different approach.

"Acopia manages 100 percent of traffic," says Liddle. "We didn't take over control of the full file system, which makes it more flexible — companies can implement it a little at a time rather than being forced to go all in. It's best to get into file virtualization gradually."

Analyst Enthusiasm

The analyst community is getting on the FAN bandwagon, too. Companies interviewed in a recent IDC (Framingham, Mass.) study reported that file virtualization allowed them to reduce storage costs between 50 and 80 percent, while improving management efficiency as much as 90 percent.

"File virtualization solutions address three key business requirements: the need to consolidate dispersed corporate information onto more easily managed NAS systems; the need to enable more effective use of business information; and the need to reduce the cost of doing business," said Richard Villars, a storage analyst for IDC.

Brad O'Neil, an analyst at Taneja Group of (Hopkinton, Mass.) believes file virtualization adds a new facet to storage.

"A FAN is ultimately about applying business-level controls and intelligence to files," said O'Neil. "This was not possible with block-level data that is necessarily void of business- or application-level context."

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