The compelling economic benefits of deploying scale-out NAS have the technology increasing its footprint in the general storage space.By Terri McClure
Unstructured data will make up 80% of the information in the corporate data center by 2012. Much of that will continue to be the type of file data IT managers have dealt with for years -- home directories and file shares -- but new file storage requirements are also growing in importance and impact. The massive amount of rich file data generated by audio, video and rich graphics, combined with Web 2.0 applications, is creating demand for innovative file storage products that can economically scale bandwidth and performance to heretofore unheard of capacities. Scale-out NAS refers to systems designed from the ground up for economically dynamic scale and support of extremely high-bandwidth applications. Enterprise Strategy Group (ESG) defines scale-out NAS as systems that can be independently scaled in multiple directions -- processor, bandwidth or capacity -- and managed as a single system in a global namespace. Scale-out NAS has seen early adoption in media and entertainment, as well as in high-performance computing (HPC), but the combination of out-of-control file data growth and richer file formats is bringing the requirement for scale-out systems squarely into the data centers of corporate America.
Scale-out NAS architectures have a number of cost advantages over scale-up products.
Low entry cost. The entry cost for scale-out systems varies depending on the minimum configurations supported. Most systems start as small as two nodes and scale out from there. With clustered scale-out systems, you can add resources as needed.
Just-in-time scalability. Because of their modular nature, there's no need to buy (and power or cool) frames, power supplies and mostly empty cabinets in advance of storage capacity. Capacity and/or performance can be added as needed.
Riding the commodity curve. Because users don't need to buy frames, processors or disks far ahead of time, they can typically get better pricing as Intel processors and disk prices decline in cost over time.
Higher utilization rates. Better utilization means deferred purchases of new capacity. Because all of the NAS heads in scale-out systems can address the entire pool of usable capacity in the cluster, there's no capacity locked away behind underutilized NAS heads.
Reduced change management planning cycles. When one file is multiple terabytes in size, conventional three- or six-month change management planning cycles are no longer effective. Requirements are unpredictable and time to provision is more important than ever. The modular and easily scalable characteristics of scale-out NAS allow for extremely fast provisioning.
Non-disruptive technology refresh. In a clustered NAS architecture, everything is redundant -- data paths, NAS heads and the data itself. Several scale-out vendors provide both forward and backward compatibility with new versions of hardware, firmware and software, so new versions can co-exist in the same system as older versions. There are also several scale-out vendors that provide non-disruptive file migration between nodes. The combination provides users with the ability to do rolling upgrades, plugging new nodes into the system and unplugging nodes when they need to be retired.
Ability to scale capacity without scaling headcount. Essentially, it should be just as easy to manage a clustered storage system with 100 nodes as it is to manage one with two nodes. Scale-out NAS systems enable this through a global namespace. In layman's terms, a global namespace is a virtual representation of a group of physical file systems. It sits between clients and the assorted file servers in a given environment, and adds a layer of abstraction that divorces what the client sees as mount points from the physical server mount points. It's the "secret sauce" that enables a single point of management and non-disruptive data migration.
Automated, policy-based management. Removing the need for human intervention in low-level storage management functions is another way that scale-out NAS reduces management cost. Most systems are plug-and-play -- add a storage or processor node, and the system self-discovers and expands the file system, and then incorporates it into load-balancing algorithms on the fly. There's typically no disruption of service and no requirement to plan data layouts, create LUNS or migrate data.
Based on the compelling economic benefits of deploying scale-out NAS products, it's no surprise that recent ESG research indicates scale-out NAS is increasing its footprint in the general storage space. A recent survey of more than 500 IT managers in North America and Western Europe found that 11% of those surveyed indicate they use scale-out NAS systems today, and 38% plan to deploy it within the next 12 months. Another 37% are actively investigating the technology. Forty-two percent of the IT managers surveyed say they're looking at scale-out options because of management efficiencies. The bottom line: Scale-out products offer economics that just plain work when it comes to managing vast amounts of file data.
BIO: Terri McClure is a storage analyst at the Enterprise Strategy Group, Milford, Mass.
This was first published in February 2009