How Scalable NAS Cuts Costs

By | May 19, 2006

In enterprise storage, scalability is the key to cutting costs. A highly scalable storage platform simplifies management by accommodating growth without the need to create, pay for and maintain new silos of storage. Given this mindset, it’s ironic that scalability is not a strong point in today’s enterprise NAS platforms. Devices that were touted as highly scalable ten years ago have now evolved into expensive, labour-intensive systems as they’re multiplied to meet rapidly expanding requirements.

To address this costly situation, an increasing number of NAS vendors are offering new NAS products that integrate powerful storage management technologies. By enhancing scalability – often by many orders of magnitude — these advancements allow IT staff members to effectively administer and protect far more data, with less ongoing disruption to users, than was ever possible before.

NAS proliferation can be triggered when one of two limits is encountered. The first is capacity. All devices have a hard stop beyond which they cannot grow, and practical limits may be exceeded before that hard limit is reached. When you factor in requirements for snapshots and management, most devices will not grow beyond 70% of their rated terabytes.

The second limit is performance. File delivery consumes processor power, and processors can become a bottleneck that increases response times and decreases user satisfaction. Performance limits are just as real as capacity limits, and they can be harder to anticipate since performance requirements are notoriously difficult to predict. Because most NAS devices tie processors to specific storage space, resolving a processor bottleneck creates the same annoyance as resolving a capacity limit: user and data migration.

An ideal NAS solution would address both capacity and performance scaling with the flexibility to add processor power and space as needed—on demand, and without limits. And ideally this change could be accommodated in the middle of the work day with zero system downtime. Finally, the perfect solution would start at an affordable price point and grow continuously to enterprise-scale as needs expand. While this sounds like a tall order, these objectives are precisely what next-generation scalable NAS solutions are intended to achieve.

Scalable NAS refers to a new generation of file-based storage solutions that comprise not one solution but a variety of approaches addressing the need for seamless file storage growth. The starting point for all of them is virtualisation. On one hand, it’s true that as a standalone product, storage virtualisation has a chequered history, rife with bloated promises and inconsistent execution.

But outside of the storage world, virtualisation thrives. VMware, for example, is a highly successful server virtualisation solution that allows virtual servers to reside within a cluster of general-purpose servers. Each of the virtual servers exists as an application environment that can be moved among different physical servers to scale processing power and provide failover. This allows users to provision these resources when needed. Storage systems can benefit from the same type of virtualisation to escape bandwidth limitations.

Scaling bandwidth

Like VMWare’s virtual applications servers, some scalable NAS solutions incorporate virtual NAS servers that can be moved transparently among physical NAS devices. This eliminates the fixed user/device mapping that complicates growth in conventional NAS, allowing processing power to be effectively allocated when and where it’s needed without the need to disrupt users.

Capacity management made easy

To simplify capacity scaling, scalable NAS includes virtual capacity. Again there is a proven analogy in the systems world. Virtual memory allows different types of memory to be deployed in a single environment, which lets applications run continuously even as the memory supporting them transforms. In the storage world, virtual capacity provides the same flexibility, simplifying capacity growth and enabling tiered storage deployments.

Scalable NAS delivered in NAS Gateways

One type of Scalable NAS solution, called the NAS Gateway, integrates processor and capacity virtualisation within an appliance-like NAS device to gain the benefits of fluid resource scaling without the complexity of multi-layered solutions. The resulting scalability enables a consolidation platform that delivers real ROI. By collapsing hundreds or thousands of Windows servers to a single NAS environment, administrators save countless hours on tasks such as management, backup, capacity additions, and user and group authentication.

Huge money savings

A case study helps to illuminate the potential savings. Assume a company has 1,000 Windows file servers used for departmental file sharing and home directory storage. According to Forrester, the cost to manage those servers–including software/hardware updates, anti-virus, and backup–runs about $5,000 annually per server. If those devices are consolidated to NAS Gateways at a ratio of 40 Windows servers per node, the management savings per NAS Gateway would total about $190,000. If we assume capital cost of $65,000 for the NAS Gateway, the device pays for itself in less than 4 months. Across the deployed server base, total savings would amount to over $3 million in the first year alone.

Further savings arise from the NAS Gateway’s pooled storage architecture. Because these devices virtualise the backend storage, they share a single pool of capacity. This boosts capacity utilisation from the typical 30% usage found in distributed environments to the 60% usage found in consolidated settings. Since the capacity is used more efficiently, the company needs less of it—50% less.

So, if the company had 20TB of storage prior to consolidation and was looking to add another 20TB, at the current cost of $10,000 per terabyte—a statistic cited by Gartner—it could put off the additional purchase and save some $200,000 in the process. Add that to the $3 million in server savings, and the company saves $3.2 million in the first year alone.

Open storage benefits

Beyond virtual processors and virtual capacity, there is a third concept from the systems world that will benefit scalable NAS: open storage. Today’s NAS is proprietary; a single vendor typically provides both the storage and the processing power. This drives up costs and limits flexibility. In the systems world, open systems eclipsed closed. And the same will happen in storage as open storage displaces today’s monolithic storage. For users deploying enterprise-wide file services, savings up to 50% will result from the enhanced sourcing flexibility and the ability to deploy both new and legacy storage resources within one environment.

NAS Gateways become the perfect catalyst for the transition to open storage. Because clients and servers access data from the Gateway, not from the storage, the NAS Gateway shields all other devices from the underlying complexity of working with heterogeneous storage.


Virtualisation has been around since IBM mainframes ruled the data processing world, but we have yet to fully realise its promise in the storage world. This situation is changing as a small group of advanced vendors are applying the technology to scalable NAS file services environments that enable users to dramatically consolidate their server populations on NAS gateways while realising reduced complexity, enhanced manageability and unprecedented flexibility.

This technologically elegant solution has the additional virtue of being financially alluring. Depending on individual user requirements, the combination of scaleable NAS Gateways and open storage strategies can save users huge amounts of money while cost-efficiently reshaping their IT infrastructures

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