Application delivery vendor F5 Networks has introduced two new file storage virtualization appliances, bringing to five the number of hardware appliances in its ARX line. Using virtualization technology, the ARX1500 and the ARX2500 make it easier to move data around a company's network regardless of which physical storage device it is in, said F5.

The new models are targeted at small to midsize enterprises that have to manage growing amounts of data but don't need or want F5's high-end ARX4000. The ARX1500 is positioned between the ARX500 and ARX2000, offering eight 1-gigabyte Ethernet (GbE) ports, throughput of 3.2 gigabits per second (Gbps), and capacity of up to 768 million files, while the ARX2500 is positioned between the ARX2000 and the top-of-the-line ARX4000. Its specifications include four 1-GbE and two 10-GbE ports, throughput of 8 Gbps, and capacity of up to 1.5 billion files. F5 also offers the ARX-VE (virtual edition), meaning it is not a hardware appliance.

The ARX line improves storage quality of service by eliminating the restrictions that occur in physical storage environments in moving files among different devices, said Renny Shen, product marketing manager at F5 Networks.

"If you're running out of capacity in your file-share environment, wouldn't it be nice if you could add in more capacity or move some of these files to a less utilized storage device without causing user-access [restrictions]?" Shen said.

A key attribute of the ARX line is its global name space, in which all the storage devices on a network are viewed as one large pool of storage, said Shen. File virtualization presents a logical representation of file systems throughout storage, decouples user access from the physical location of files, and masks changes to the underlying storage assets from applications and users. The ARX line also automates data-management policies in the areas of data migration, storage tiering, and capacity balancing.

Virtualization was first adopted by enterprises in their server environments, where a server operating system was decoupled from the physical server, allowing multiple operating systems, or virtual servers, to run on the same machine. But storage virtualization operates on an entirely opposite principle, said Shen.

"Server virtualization is when you try to make one physical server into multiple virtual servers. But with storage virtualization what you're trying to do is take multiple physical storage devices and make it look like a single [virtual] storage device," he said.

In Demand, the company that delivers video streaming for U.S. cable TV companies including Comcast, Time Warner, Cox, and Bright House Networks, operates two of the high-end ARX4000s, which store 300 terabytes (TBs) of movies and TV shows, with another 1 TB of content added per day, said Michael Raposa, senior director of infrastructure.

The F5 ARX appliance knits together the different storage appliances, which Raposa refers to as "mount points," using Microsoft's Distributed File System (DFS) software.

"What's presented to the F5 is 30-plus mount points that are each 30 terabytes. F5 knits all of those mount points together into a single presentation to the client," he said.

The advantage of storage virtualization for In Demand is better load balancing, storage tiering--putting frequently used files on faster hardware than little used files, and the ability to use different brands of storage hardware to avoid vendor lock-in, Raposa said.

F5 Networks--which offers other virtual application delivery technology--declined to share specific pricing information on the new ARX1500 and ARX2500, but said its ARX line overall is priced at between $30,000 and $200,000.

Storage virtualization enables IT to eliminate storage volumes with hard characteristics, while file virtualization is about abstracting the link between files themselves and their references. The result? Freedom for IT--and users--from regimented storage structures. Read our report now. (Free registration required.)