NAS gateways tame file growth

Posted on December 01, 2005

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Consolidation and scalability help cut costs, improve manageability, and deliver better service.

By David Hill

Enterprise-class NAS gateways are not so much about NAS-SAN convergence (which is simply a consequence) as they are about the declaration of independence of file serving intelligence from its associated storage. In other words, NAS gateways do the same thing for files (although not in the same way) as SANs did for blocks (i.e., decoupling of server and storage).

“Cut costs, improve manageability, and deliver better service” seems to be the mantra of IT organizations, especially in trying to manage the unruly growth of their storage. Today, the files that need to be managed extend beyond what is centralized in the data center to files distributed to workgroups and departments and even distributed geographically to remote sites.

More and more enterprises are coming to realize that the file growth crisis either exists now or is going to exist very soon. The problem is typically assigned to the data center, which has the concentration of IT skills, experience, and disciplines to manage enterprise-class storage. And data centers have the resources to focus effectively on cutting costs, improving manageability, and delivering better service.

However, repeating the mantra and delivering on it are two different things. How is the data center going to deal with the file management growth crisis?

Putting in more file servers is an unpalatable choice, as even the current number of file servers is typically already seen as a culprit due to capacity scaling limitations, lack of cross-filer file sharing capability, and the burden of backing up servers individually. Although adding more distributed NAS appliances might help, the enterprise is likely to have exhausted that avenue by the time it turns to the data center.

The traditional way of delivering NAS is through a close coupling of the NAS “head” and its associated (direct-attached) storage for ease of integration and management. These integrated NAS appliances work well when targeted to a single application or bounded set of applications where optimization of some key parameter-such as capacity scaling, high performance, or specialized file service management functionality-is paramount.

NAS gateways

However, integrated NAS appliances typically do not have the reconfiguration flexibility capabilities of enterprise-class NAS gateways.

The difference between an integrated NAS appliance and a NAS gateway sounds simple: A NAS gateway is simply a NAS head without the direct-attached storage (DAS). The NAS head and the storage are decoupled. That difference is profound, as decoupling the two is the real essence of storage networking. Decoupling unleashes the full power of storage networking that was previously unavailable to NAS.

NAS-SAN convergence is often touted as the primary benefit of NAS gateways, but it’s not necessary to have a SAN to take advantage of enterprise NAS gateways (although it may be useful). The ability to negotiate storage purchase decisions separately from NAS-head purchases, and/or the ability to protect existing storage investments, are valuable benefits, but again that’s not where the real power of NAS gateways resides.

The real power resides in one word: flexibility. Flexibility is ease of modification and adaptation and ease of designing, configuring, and tailoring a solution to the file management crisis that is built around the resources and capabilities of your organization. The alternative is to buy into a pre-configured solution that as a “force-fit” may or may not solve the problem.

Solving the file management crisis is not a point-in-time event; it requires laying a foundation that can serve as a platform for future growth as well. The solution must be able to scale non-disruptively on a number of dimensions.

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In implementing an enterprise-class NAS gateway strategy, view your organization’s “present” as the stage of concentration (see figure). The “past” was the stage of consolidation, and the “future” is the stage of scaling, where the focus is on being able to adjust to change with minimal impact.

The power of consolidation

Consolidation is important in IT today, mainly because reducing the number of anything lowers costs, simplifies management, and increases availability. Enterprise-class NAS gateways enable three types of consolidation possibilities:

  • File-server consolidation-A small group of NAS heads can replace a larger number of independent file servers;
  • Storage consolidation-Isolated islands of storage that were hard-wired to specific file servers can be aggregated into a common pool of storage; and
  • Site consolidation-Distributed NAS with its associated storage can be aggregated at a data-center level.

Consolidation is the process of achieving a state of concentration, which enables you to

  • Provide unified file administration;
  • Create a single logical pool of storage; and
  • Cluster NAS gateways.

The power of scaling

File growth is likely to continue, so enterprises need to scale harmoniously while maintaining the key capabilities from the concentration stage.

The traditional dimensions of enterprise-class NAS scaling revolve around bandwidth (e.g., NFS operations per second) and capacity. With the advent of denser disk drives and clever packaging to squeeze as much as possible out of standard rack space, vendors can claim scalability because of the large number of terabytes that can be supported. And solid schemes exist for scaling bandwidth in integrated NAS appliances.

But the power of a clustered NAS gateway system is to be able to scale bandwidth and capacity independently. That increases flexibility, as IT can match demand to need when the demand for either bandwidth or capacity grows disproportionately.

The other power is to be able to scale NAS gateways non-disruptively in two dimensions-“out” by adding more NAS heads in a cluster or “up” by adding more-powerful NAS heads (or upgraded firmware). In addition, the logical pool of storage should also be able to grow non-disruptively.

Enterprise-class NAS gateways enable cost reduction, improved management, and increased service levels via consolidation, concentration, and scaling (see table). Of course, there is a caveat: The benefits are not necessarily exclusive to a NAS gateway solution, and any particular NAS gateway solution may not deliver all of the benefits.

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Many vendors provide integrated NAS appliances, but surprisingly few vendors play at the enterprise-class NAS gateway level. EMC and Network Appliance are the leaders in this field. They offer both integrated NAS as well as NAS gateways. IBM is a player via its reseller relationship with Network Appliance. Hewlett-Packard also has a high-end clustered NAS gateway product. Smaller vendors such as BlueArc, MaXXan, and ONStor also sell enterprise-class NAS gateways.

All of these vendors compete on a number of variables, including clustering, data sharing, grid computing, global namespaces, breadth of heterogeneous platforms supported, and virtualization.

Enterprise-class NAS gateways have not received the attention they deserve. The real power of these gateways lies in helping IT organizations solve the growing problem of how to tame the file server growth tiger through the flexibility delivered by consolidation, concentration, and scaling.

David Hill is an analyst at the Mesabi Group LLC (www.mesabigroup.com) in Westwood, MA.


CASE STUDY: North West turns to NAS gateways

North West Geomatics Ltd. is a Calgary-based aerial data acquisition and geospatial data content provider. Mapping firms, government agencies, and other organizations use the information processed from data that is captured from North West’s fleet of aircraft. Each aircraft typically generates between 150GB and 500GB of data per day, so it is no surprise that North West has about 140TB of storage capacity.

North West processes large image files (typically 2GB chunks) through a number of steps before delivering the final images to its customers. An existing combination of servers in conjunction with external servers in a SAN did not scale effectively for these large image files in terms of manageability, cost-effectiveness, performance, and data availability.

North West examined a number of NAS solutions that deliver the ease of management, performance, and availability that they required. The company chose a NAS gateway from ONStor to deliver the benefits of NAS without requiring the additional cost of replacing disk storage and/or the SAN they already had in place.

As part of delivering the manageability, performance, and availability benefits, the enterprise NAS gateway enabled the consolidation of Windows, Linux, and Unix servers into one scalable environment that includes the ability to scale capacity and bandwidth independently. That means that North West can balance its performance requirements with its capacity requirements without having to tie its NAS-head purchase decisions with its disk storage purchase decisions. North West is also leveraging the gateway’s virtual server capability for load-balancing and fail-over, which delivers both performance and higher availability.


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