By Lisa Coleman
BlueArc claims it has solved the "islands-of-storage" dilemma that plagues administrators who need to scale network-attached storage (NAS) file systems.
Last month, the company released its next-generation NAS system, called Titan SiliconServer, with a single file system that can support volumes up to 256TB and hardware-based clustering, allowing for a "continuous cluster."
NAS is notorious for not scaling well in performance, but scaling capacity can also pose problems. Typical NAS devices have a maximum of about 6TB of data in a single file system, according to
Geoff Barrall, BlueArc's CTO. To scale beyond that, traditional NAS appliances are clustered together but sometimes can be clustered only in pairs, resulting in "islands of storage" that are managed separately, says Barrall.
BlueArc's Titan uses hardware-based clustering that enables any number of Titan "heads" to be clustered, eliminating islands of storage.
Analysts such as Randy Kerns, a senior partner at The Evaluator Group consulting firm, contend that Titan is just another way of aggregating storage and it doesn't necessarily solve the islands-of-storage problem. Barrall counters that Titan makes storage consolidation a reality.
However, NAS market leaders such as Network Appliance are working on solving the scalability problem, and many vendors have software that allows disparate groups of NAS devices to be managed as one system.
Last year, Network Appliance acquired Spinnaker Networks, gaining an operating system that allows scalability across hundreds of geographically dispersed NAS appliances, although the integration of Spinnaker's file system with Network Appliance's file system may take years (see "Network Appliance acquires Spinnaker Networks," InfoStor, December 2003, p. 1).
Barrall contends that hundreds of NAS boxes are not necessary if you have one device and one file system that can scale into hundreds of terabytes.
The scalability of the BlueArc file system is significant, says Stephanie Balaouras, a senior analyst at the Yankee Group consulting firm, although it is not quite a distributed file system.
"Being able to scale a single file system will be helpful for many customers in the small-to-medium business space," says Balaouras. Titan will not necessarily solve the islands-of-storage issue, she says; however it will ease management by allowing enterprises to add more storage on one system than previously possible.
BlueArc's technology is generally characterized as NAS, but it uses a non-traditional architecture. The architecture is based in hardware, not software, and uses field-programmable gate arrays (FPGAs) that are similar to reprogrammable ASICs.
In another departure from traditional NAS architectures, Titan is based on a modular blade architecture, currently consisting of four blades in one chassis for up to 5Gbps throughput. The basic configuration consists of one blade for networking, two for the file system, and one for storage management.
Optional blades can be added for I/O performance increases. A system with ATA disk drives is priced from $40,000, while a 3TB configuration with Fibre Channel disk drives is priced at approximately $100,000.
BlueArc also rolled out code that it refers to as information life-cycle management (ILM) software, which allows users to define policies for seamless data migration between tiers of storage such as nearline and archival storage.
The company also enhanced its replication to enable off-site replication between SiliconServer and other storage systems. The hardware-based replication enables servers to replicate data while serving files to users with little performance impact, according to Barrall. In addition, BlueArc released caching technology, called remote data acceleration (RDA), which consolidates data from remote offices to a company's headquarters.