When it comes to network attached storage (NAS) systems for high-performance computing applications, the most popular choice is a clustered NAS system that consists of multiple hardware elements functioning as a single device through the addition of a software management layer. Clustering NAS systems allow users to scale capacity and performance separately, and quickly.
According to Enterprise Strategy Group (ESG) analyst Mark Peters, data growth has continued as new Web 2.0 applications and IT service providers pop up in the industry, and since those companies' customers create their own data, that growth is more unpredictable than in the past. As a result, the demand for quick-scaling clustered systems is helping to create a new generation of new storage vendors with legacy vendors trying to perform new tricks.
There are two main types of products that bring together multiple NAS heads in order to aggregate processing power: clustered NAS and clustered file systems. The key difference between them is that clustered NAS systems include hardware; clustered file systems consist of software meant to be layered over multiple hardware nodes.
Vendors often point out a distinction between parallel and clustered NAS systems or file systems: true clusters use a single metadata control node, while parallel systems spread control data out over all the nodes. However, analysts say the distinction isn't a huge one. "People get all excited about implementation details," according to Data Mobility Group analyst Robin Harris. "I prefer broader terms at this early stage based on what clustered systems are defined against -- traditional storage arrays and JBODs."
Clustered NAS systems
|Isilon Systems Inc.||Isilon IQ|
|Network Appliance Inc.||OnTap GX|
|BlueArc Corp.||Titan 2000|
|OnStor Inc.||Bobcat clustered NAS gateway (no disk)|
|OnStor Inc.||Pantera clustered NAS (with disk)|
|Hewlett Packard Co.||StorageWorks EFS Clustered Gateway|
|EMC Corp.||Celerra NS Series|
|Panasas Inc.||ActiveStor Parallel Storage Clusters|
|Rackable Systems Inc.||Rapidscale Clustered Storage|
Clustered file systems
|Ibrix Inc.||Fusion Cluster File System|
|IBM||General Parallel File System|
|Parascale Inc.||Virtual Storage Network|
|Sun Microsystems Inc||Lustre File System|
|Quantum Corp.||StorNext Cluster File System|
More to come in 2008
Despite rising data growth and strong uptake in some vertical markets, such as oil, gas and media entertainment, the road for clustered NAS vendors has not been an entirely smooth one. "Companies are relatively successful, but they're making hundreds of millions in sales in this space, not billions," Peters said.
Still, analysts predict that a tipping point is on the horizon, and according to Harris, it will probably come with clustered NAS hardware code-named Hulk and clustered NAS software code-named Maui, due out later this year from EMC. "Basically, EMC will be blessing clustered storage for the enterprise -- at that more conservative people in IT will take a closer look."
Sun has also set its sights on building large clustered NAS farms for the next generation of data centers, which it expects will look a lot like Google Inc.'s homegrown farm of PCs and proprietary software. In addition to the Lustre file system cited above, Sun offers a 128-bit file system called the Zettabyte File System (ZFS), and along with other storage companies, including Panasas, is working on a new parallel-processing standard called pNFS. That standard is also expected to be finalized this year.