The NAS market will slow from a 20 percent growth rate in 2004 to roughly a 9 percent growth rate over the next couple of years, according to Gartner, but Unified Storage the marriage of SAN block-based and NAS file-based storage promises to keep the market healthy for some time to come.
Some say the Unified Storage market began to emerge when Network Appliance users started expanding their storage environments from NAS to SAN.
Jim McDonald, CTO of WysDM Software, believes that the driver, as is so often the case, has been price.
"If you look back to 1999, EMC was offering Celerra, which provided Unified Storage, so this is not anything new," said McDonald.
The problem with Celerra, as McDonald sees it, was that it used the most expensive back-end disk array (Symmetrix) and put a NAS head in front of it. "Therefore, as end users considered NAS to be tier 2 storage, they weren't prepared to pay a premium for it even with the additional performance and resiliency it provided," he said.
NetApp went the other way, notes McDonald, working with what had traditionally been considered tier 2 storage and making it available for block-based operations.
"This provided obvious cost savings and so was more readily adopted by end users," he said. "NetApp is unique among the larger players in that they come from the lower end of the market and have moved up, which makes end users feel better when using them, regardless of the realities of pricing between companies."
EMC, naturally, cites its own role in the evolution of Unified Storage.
"If you look at EMC's track record in this space, it's clear that EMC has been leading the convergence of storage networking technologies for almost a decade," said Pete Lavache, EMC's director of storage product marketing.
Lavache said EMC was first in Fibre Channel SAN storage (1998), NAS gateways for adding IP connectivity to SANs (1999), multi-path file systems (MPFS) to integrate the speed of SAN with the access and sharing of NAS (2000), and most recently, adding iSCSI to all its storage platforms (2003) as well as MPFS (2006).
Lavache says Unified Storage has become a top requirement for storage customers, a trend that Stephen Harding, director of marketing at Tek-Tools Software, also sees.
"Even the most modest of IT infrastructures, specifically in the case of storage, has become increasingly diverse and sophisticated in recent years," said Harding. More and more NetApp customers are using their storage arrays as both NAS and SAN storage, he said.
"In many cases, and in fairly large implementations as well, storage customers are using their NetApp storage systems exclusively as SANs, hoping to expand to NAS at some point in the future," said Harding. "We also see more Fibre Channel implementations than iSCSI."
The growing mix of storage protocols is driving the adoption of Unified Storage, but Eric Schott, director of product management at EqualLogic, warns that there are risks.
"There are a few inherent conflicts in the value of Unified Storage that IT administrators should consider," said Schott.
One issue, he says, is the assumption that SAN and NAS capacity will grow at the same rate. Schott believes that Unified Storage automatically assumes that SAN data and NAS services will scale at a 1:1 ratio an assumption he says is incorrect because in most environments, NAS is a minority of storage use.
The result of this assumption, he said, is that organizations are forced to pay for scaling both SAN and NAS services with unified devices, when only one service needs to be grown. This adds additional cost and complexity to the storage configuration.
The Cost of Compliance
One of the most widely accepted views in the storage industry is that compliance regulations such as Sarbanes-Oxley will increase the usage of NAS systems for archiving applications.
"These regulations have yielded increased functionality and retention requirements, but this is not limited to NAS," said EMC's Lavache. "This is one of the key elements that has accelerated the adoption of tiered storage and the usage of file-based retention capabilities via EMC's Celerra platform, as well as spurred the rapid adoption of CAS a new class of solution ideally suited to meet a host of regulatory and compliance requirements."
Harding of Tek-Tools agrees that compliance regulations have led companies to rethink what they store and how they store it, and as a result, organizations are increasingly using NAS storage for archiving.
But the same compliance regulations also encompass other data areas such as e-mail, for which NAS systems are not an option, he said. "One might speculate that there is more potential for Content Management Systems rather than NAS systems when it comes to archiving," he said.
EqualLogic's Schott agrees that compliance will raise the use of storage resources, but he adds that it has yet to be determined whether NAS is the best method for serving compliance applications.
"Content addressable storage systems are typically not based on NAS architectures," said Schott. "Rather, they typically have custom APIs for creating and accessing content. NAS system file naming and directory policies are typically non-optimal for CAS systems, as the usage model is different."
Industry analysts also predict that NAS gateways will continue to grow at a healthy pace to capitalize on existing SAN infrastructures, since some newer storage products have begun to support heterogeneous SAN storage arrays. However, they predict that unlike the Unified Storage approach, the management of NAS gateways will continue to be separate from the management of SAN arrays for block-level applications because they are usually based on different platforms.
In the next article, we'll look more at NAS gateways and the potential of low-end NAS to replace Windows file servers and to serve as a backup target for local branch offices.