NAS virtualization simplifies file management

Posted on October 01, 2005


NAS virtualization is an emerging technology that can solve the major problems that users have identified with complex NAS environments.

By Tony Asaro

As with any emerging technology, there is hype and confusion surrounding NAS virtualization. A small group of early adopters have implemented solutions from a small group of vendors, including Acopia Networks, NeoPath Networks, NuView, and Rainfinity, which was recently acquired by EMC (see “EMC rounds out virtualization,” p. 1).

The product category goes by many names, including file virtualization, file system virtualization, network file virtualization, and others. The Enterprise Strategy Group (ESG) uses the term “NAS virtualization” because from a macro level these solutions virtualize NAS systems.

Part of the confusion around NAS virtualization comes from the vendors themselves. For example, the following is Acopia’s product definition from the company’s Website: “The Acopia Adaptive Resource Switch (ARX) is an intelligent file switching system that enables enterprises to optimize utilization, increase performance, and simplify management of file storage resources.”

And here’s how Rainfinity describes its product: “By uniquely combining Network File Virtualization with specific application modules, Rainfinity enables tiered storage management, performance optimization, capacity management, and file server consolidation. By significantly increasing storage efficiency, RainStorage lowers capital expenditures and reduces the total cost of ownership.”

In the vendors’ descriptions of their products they usually don’t mention NAS systems, although NAS is requisite to their solutions. And the vendors tend to use language and terms that are specific to their products (e.g., intelligent file switching system, network file virtualization, etc.). They force people to read more to truly understand what the products do. Acopia and Rainfinity are not alone; NeoPath and NuView are also challenged with communicating what they do and why it’s important.

The following is ESG’s definition of NAS virtualization: “NAS virtualization is an intelligent device (switch, appliance, or server) and software that creates a single point of management for multiple NAS systems. You can create a single pool of file-based storage that simplifies management, provides better utilization of your NAS assets, improves the user workflow process, and enables intelligent tiered storage. Additionally, NAS virtualization is transparent, allowing companies to continue to use their NAS systems’ data management features such as snapshots and remote mirroring.”

To put it simply, NAS virtualization makes it easier to manage file-server environments. Companies may have dozens, or even hundreds, of file systems that have to be managed individually. System administrators have to manage permissions and sharing parameters for all of the different file systems and their associated users, and in an ever-changing environment this becomes a runaway train of complexity. NAS virtualization presents a single file system, mount point, or network drive letter so that changes can be made much more easily.

Having a single file system also makes it easier for users to navigate around their NAS file storage. Instead of jumping from drive letter to drive letter, it is much easier to have a single point of access through a common shared directory. This ease of access can significantly improve the workflow process.

NAS virtualization creates a single pool of file-based storage so that data can be moved between NAS systems based on capacity utilization. For example, one NAS system may be 75% utilized and another only 30% utilized. NAS virtualization can move data between these different storage systems while online, transparently to users. This data migration capability is also useful when upgrading NAS systems to new models or changing/adding vendors.

Another important aspect of NAS virtualization is its ability to move data between different tiers of storage based on performance requirements or frequency of access. Why keep files on the most expensive storage tier if no one is reading or writing to it? Again, this is done online and transparently.

NAS virtualization can be extremely valuable. However, it is frustrating that there is so much mudslinging between the vendors, who don’t seem to understand that all of this negative commentary about one another slows down the progress of NAS virtualization as a whole. What these vendors may not understand is that their biggest competition is not one another, but a lack of awareness of their solutions in the end-user community.

Regardless of the mudslinging, proof of the value of NAS virtualization is in customer implementations. ESG has spoken to a number of companies that have installed NAS virtualization solutions and they have solved workflow issues, management complexity issues, capacity utilization deficiencies, and performance problems. The fact that one solution provides its own global namespace and another uses a standards-based approach is an issue that may or may not matter to users. However, since they are differentiators the vendors tend to focus on these types of issues. But whether any of these issues are important depends on the user’s requirements.

NAS virtualization solutions provide a global namespace. That’s a fancy term for the ability to create a single view or management point for multiple file systems. NeoPath, NuView, and Rainfinity/EMC use Microsoft’s DFS as their global namespace, and Acopia uses its own implementation.

NAS virtualization solutions sit in front of heterogeneous file systems from vendors such as EMC and Network Appliance to manage them better. The beauty of this approach is that users can leverage their existing NAS assets and data management software, processes, and policies.

EMC’s acquisition of Rainfinity will change the dynamics of NAS virtualization by creating greater awareness of the technology, which is good for all of the vendors in this space. As it did with its Centera active-archive platform, EMC can create and elevate markets.

Over time, more and more intelligence will be integrated into NAS virtualization products, and back-end storage systems will become more commoditized. It is not unrealistic that companies will use NAS virtualization to manage commodity-based NAS appliances built on Windows and Linux, creating low-cost, scalable, and intelligent NAS “grids.”

NAS virtualization is compelling and can be used to re-invent NAS environments without having to do any forklift replacements. In fact, the process should be relatively easy.

However, the market is still emerging and there are very few players. EMC is the first leading storage vendor to put a stake in the ground. Network Appliance resells NuView’s StorageX as Virtual File Manager (VFM) and is in the process of integrating technology it acquired from Spinnaker (see “Network Appliance’s three-pronged approach to virtualization,” above). We’ll have to wait and see what the other large vendors-Hewlett-Packard, Hitachi Data Systems, IBM, and Sun-will do in this space.

Based on ESG’s research, it is apparent that many companies are prioritizing NAS virtualization and that NAS is becoming more strategic. Today the needs are very tactical-solving management and usability problems. However, the implications are very strategic. NAS virtualization has the potential to change the dynamics of how users implement storage networks. NAS has file awareness that provides a level of intelligence that cannot be achieved with SANs. The ability to manage, access, and leverage data is more easily achieved today using NAS, and more capabilities will be added over time. NAS virtualization can create even greater levels of intelligence, scalability, and ease of management, supporting heterogeneous environments and solutions built on low-cost commodity hardware.

Tony Asaro is a senior analyst in the Enterprise Strategy Group’s lab operation (www.enterpris

EMC #1 in NAS, but . . .

By Dave Simpson
According to figures from International Data Corp. (IDC), EMC held on to the top position in NAS revenues in the second quarter of this year, with $191 million in worldwide revenues-up 16.9% from the second quarter of 2004. Network Appliance came in second, with $167 million in NAS revenues, up 6.5% from Q2 2004.

IDC claims that EMC had a 40.2% share of NAS market revenues in the second quarter, compared to a 35.2% slice for Network Appliance.

However, Network Appliance objects to IDC’s policy of including shipments of content-addressed storage (CAS) platforms in its NAS revenue tracking. If EMC’s Centera CAS platform revenues were not included in IDC’s NAS numbers, the gap between EMC and NetApp would tighten considerably.

IDC defines NAS as “an external disk storage system that attaches to a LAN, communicates at a file level, and contains an internal operating system optimized for file serving.” However, Network Appliance officials argue that CAS systems do not communicate using file protocols (NFS or CIFS) and are optimized for storing objects, not files. In short, CAS is not NAS, according to NetApp.

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(Because of IDC’s categorization scheme, Hewlett-Packard’s and IBM’s NAS revenues are also boosted due to sales of their CAS platforms.)

Other research firms typically track CAS as a separate product category.

What’s surprising in the NAS market-share numbers and revenues is the precipitous drop between the top two vendors (EMC and Network Appliance) and the rest of the NAS pack (see table). Compared to NetApp’s $167 million in quarterly revenues, Hewlett-Packard came in third with only $30 million in Q2 revenues (6.4% market share), followed by Dell ($20 million, 4.1% market share) in fourth place, according to IDC’s figures.

In virtually every category of disk systems tracked by IDC, EMC was the leader in Q2 revenues.

The one exception was in the overall disk storage system market, which includes both internal and external disk shipments, where Hewlett-Packard came in first, followed by IBM, EMC, and Dell.

One IDC figure that Network Appliance did not quibble with was the research firm’s estimates for iSCSI market shares, which put NetApp in the leadership position with a 41.6% share, followed by EMC with a 26% cut of worldwide iSCSI disk array revenues. (Overall, the iSCSI market grew 140% year over year.)

However, even the iSCSI category can be contestable because, although IDC tracks revenues from disk systems shipped with iSCSI capabilities (which virtually all of Net-App’s systems have), that does not necessarily mean that customers are using the iSCSI functionality.

Network Appliance’s three-pronged approach to virtualization

By Dave Simpson
Network Appliance’s virtualization strategy may seem confusing because the “v-word” comes up in different contexts, but it can be simplified by viewing it in three product categories, one of which is a work in progress.

NetApp’s V-Series platforms are based on the company’s gFiler NAS-SAN gateways and the 7G version of its Data ONTAP operating system software. The V-Series platforms can be attached to other vendors’ SAN-based disk arrays. One factor that differentiates the V-Series from some other vendors’ virtualization engines is that it supports both blocks (via Fibre Channel and iSCSI) and files (via NFS and CIFS), which NetApp refers to as “unified storage.”

In a second virtualization product category, NetApp’s Virtual File Manager (VFM) is a version of NuView’s StorageX NAS virtualization platform, which addresses the problems associated with NAS “islands” or “silos.” Net-App refers to this product category as NAS aggregation and migration, while others refer to it as NAS virtualization, file virtualization, network file management (NFM), or other terms. VFM software can be used in heterogeneous NAS environments and provides centralized management of disparate file servers. Other players in this space include Acopia, NeoPath, and EMC via its acquisition of Rainfinity (see “EMC rounds out virtualization,” p. 1).

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Finally, Network Appliance is in the process of integrating technology from its acquisition of Spinnaker Networks (including the SpinFS file system) with Data ONTAP, the WAFL file system, and all of NetApp’s layered applications (e.g., SnapLock, LockVault, etc.). Essentially, this integration will unite all of the features of NAS aggregation/migration with the native NAS file system. This piece of Net-App’s virtualization is a work in progress.

According to Jeff Hornung, vice president of enterprise file services and storage networking at Network Appliance (and formerly with Spinnaker), the company has already delivered pieces of this integrated product and will ship the first integrated version by year-end. However, that version will be incomplete and will be targeted primarily at high-performance computing (HPC) environments such as the video/entertainment, oil and gas, and life sciences markets, according to Hornung. A final integrated version is not expected for another 12 to 18 months, although pieces will be phased in over that period.

Today, NetApp sells Spinnaker’s proprietary SpinFS and SpinServer products, which are not designed for heterogeneous environments. These products provide features such as the ability to separate physical storage from logical storage, and the ability to do transparent data moves (e.g., while maintaining full data access) without changing namespaces.

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