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The changing face of scale-out network-attached storage

We explore the challenges associated with implementing scale-out network-attached storage, provide advice for firms considering scale-out NAS and discuss the cloud as a NAS tier.

The face of network-attached storage (NAS) is changing. Enterprise IT shops are increasingly seeking out the latest wave of scale-out network-attached storage systems that better support file I/O-intensive applications and scale to multipetabytes of data under a single system image. Meanwhile, small- to medium-sized businesses (SMBs) are contemplating testing cloud-based file storage.

In this podcast interview, Terri McClure, a senior analyst at Enterprise Strategy Group, shares her predictions that the majority of data storage will be scale-out within a few years and that the cloud is rapidly emerging as a NAS tier. Read the transcript below or download the MP3. How has NAS changed during the last year or so? What are the major new developments?

McClure: The biggest change seems to be the emergence of scale-out as a viable enterprise IT solution. Scale-out NAS really started in niche markets roughly a decade ago, so it's certainly not brand new. These systems typically excelled in handling high-throughput applications such as media, entertainment, geospatial imaging or bioinformatics applications, and that's because of the bandwidth they can provide. But what is new is that we've seen a class of products emerge that fits the more file I/O-intensive performance requirements typical of enterprise IT shops. These systems are coming from the likes of BlueArc and Hitachi Data Systems, which resells BlueArc. EMC’s Isilon has made advances in this area, and the Hewlett-Packard X9000 would be another example.

Aside from the vendors bringing out new offerings, we're also seeing end users pull for these types of systems, primarily for the scalability, since these systems often scale almost linearly from a capacity and performance standpoint into the multipetabyte range and maintain a single system image. That makes them very easy to manage and helps users get much better utilization rates. So, we're actually seeing it come at IT from both directions -- the vendor push and the user pull for these types of requirements. What advice do you have for IT shops that are considering scale-out NAS but have experience only with traditional NAS products?

McClure: Use case is really important here. Because of where these systems came from, some systems have advanced from the early niche market days and can handle more small-file, I/O-intensive applications. But many are still optimized for large-file sequential performance. Also, since the markets these systems originally served didn't require a lot of the advanced features common to traditional NAS systems, like synchronous remote mirroring or read-only snaps, many of the scale-out systems still lag in that type of advanced functionality and the overall functionality still varies quite a bit. With some systems, they can tier within a global namespace and automate data movement and migration all the way out to tape, while with others, you just get one flavor or tier of performance.

I would suggest it's really important to get references to talk to, specifically users that have similar application workload and data protection requirements, to make sure the vendor you're dealing with can meet the performance and functionality requirements you have for your enterprise IT apps. What are the main challenges associated with implementing scale-out network-attached storage?

McClure: These systems have a multi-node nature. There's a lot of NAS heads that are connected together and grouped and managed within a single system, but that also means greater network connectivity. You have to plan for additional network connectivity, and sometimes upfront there may be more power and cooling requirements because with some systems you have to deploy a minimum of three nodes just to get into the system for availability and performance requirements.

Interestingly enough, as the system grows, because of the better utilization and granular nature at which you can scale -- we call it just-in-time scale with scale-out systems -- the power and cooling advantage will actually swing the other way, and scale-out systems will carry an advantage when it comes to utilization and power, cooling consumption. But to start out with, the network connectivity requirements you have to plan for are really important, and the additional possible power and cooling requirements [are] also. Can you foresee a day when scale-out NAS will represent the majority of the network-attached storage systems in use?

McClure: Yes. We recently published a scale-out storage forecast in which we predicted that scale-out storage will make up 80% of all external network storage systems by 2015. Interestingly enough, we didn't separate SANs [storage-area networks] and NAS in our forecast, and that's because we believe that over time, scale-out systems that support both block and file storage will be the norm. We actually expect the norm will be systems that can scale in multiple dimensions: scale up, scale out and scale linearly. If a system can scale in multiple dimensions, we actually classified them for the purposes of this forecast as scale-out systems. That said, we don't see traditional scale-up systems going away. They'll still be around, partly because in storage nothing ever seems to go away and partly because this is very use-case dependent. Workloads will continue to be stratified, and so will the storage that supports them. What about using the cloud as a NAS tier? Is that ready for prime time?

McClure: Scale-out's still early in the enterprise IT adoption cycle, and cloud's even earlier. We're starting to see it emerge, and it just makes sense. As a small- or a mid-sized business or a startup, why invest all the capital equipment to build your own IT? Nasuni is doing pretty well with its solution. F5 [Networks] is seeing some uptake with its ARX tiering to the cloud. We're certainly seeing it begin in the commercial space. And look at the adoption of Dropbox; I don't know anybody that doesn't use it nowadays. And that's basically a file system in the sky, in the cloud. Our research also indicates that users are willing to invest in IT as a service for both infrastructure-as-a-service and software-as-a-service [SaaS]. Our 2011 IT spending intentions survey found that spending for cloud-based services in 2011 is up substantially against 2010. It's still not at the top of the list, it's about halfway down the priority list, but it made a big jump in enterprise IT priorities this past year. How are data storage vendors addressing the challenges associated with using cloud as a NAS tier, and in what areas do they still have a lot of work to do?

McClure: Most of the work is related to making users feel comfortable with the technology. The biggest inhibitors continue to be trust, security and concerns about data availability. And it doesn't help when we hear about outages. There are best practices that can be deployed to mitigate the concerns. Nasuni, TwinStrata, StorSimple and Panzura all provide gateways that allow users to do things like mirror between clouds, so you're insulated from the outage of one cloud by servicing your data request from the other, or encrypting and snapshotting for data availability.

We're still early in the learning curve, and we're still developing best practices. Things are moving forward fast so it's imperative to keep abreast of developments. That's the No. 1 thing I'd suggest. You have to keep abreast of the developments in the industry because things tend to take forever to change in IT. But with what's happening on the cloud front today, things are changing faster than I've seen them change in the last 20 years, so it's important to keep on top of what's going on out there.

Read the entire tutorial on scale-out storage

  • The changing face of scale-out network-attached storage
  • Isilon scale-out NAS helps production company manage 250 TB
  • Scale-out NAS, object storage, cloud gateways replacing traditional NAS


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