NAS, SAN -- you name it, Nielsen Media's got it

Faced with the steady growth of its Windows systems management responsibilities, Nielsen Media Research began planning to build a consolidated network-attached storage (NAS) environment. Before it finishes, however, the company will have created a combined multitier, multivendor, NAS/storage-area network (SAN) infrastructure that supports numerous corporate business units and provides a foundation for a variety of innovative storage strategies.

Until it embarked on consolidating its NAS systems in early 2004, the company hadn't been particularly innovative with storage. It had been storing its Windows files on direct-attached storage. "We expected to consolidate a lot of DAS into NAS," says Robert Stevenson, technology strategist at Nielsen. Nielsen's technology center is located in Oldsmar, Fla., while its U.S. corporate headquarters is in New York.

Nielsen Media Research is part of VNU, a Netherlands-based international information and media company. The company employs 36,000 employees worldwide in more than 100 countries and generates 3.9 billion euros in revenue, with more than half coming from North America.

Nielsen Media Research is widely recognized as the TV ratings company, providing television audience estimates for broadcast and cable networks, television stations, syndicators, cable television systems, satellite TV, advertisers and advertising agencies. Beyond the U.S., it is active in more than 40 countries, providing television and radio audience measurement, print readership and custom media research services.

Consolidation -- and Beyond

Nielsen's NAS consolidation was an effort that many organizations undertake when facing the proliferation of Windows servers with DAS. Such consolidation typically lowers the cost of ownership while improving service levels. In Nielsen's case, however, a new issue suddenly arose to complicate things.

"At the same time we were doing our NAS consolidation, we were also building a sizable enterprise SAN," Stevenson explains. "We didn't want two separate pools of storage." Such a situation would undercut any gains the company achieved from storage consolidation.

Instead, the storage planners shifted to a NAS gateway solution. In this way, the NAS storage could take advantage of the disk capacity of the SAN, with the gateway providing the NAS access to what would end up as a consolidated enterprise SAN/NAS infrastructure.

Further complicating the situation was Nielsen Media's highly heterogeneous, multitiered storage environment. Not only did the company set up multivendor storage tiers with its block storage, but it also intends to set up similar tiers for its NAS storage.

Given that Nielsen Media's primary product is data, it's not surprising that data storage looms large. The company has established a four-tier storage architecture, explains Stevenson. The first tier consists of primary, mission-critical data that is stored primarily on the SAN. The second tier handles business-critical data, some of which is stored on NAS.

The third tier handles noncritical data, often using lower-cost NAS. The fourth tier performs archiving and relies on low-cost iSCSI arrays from Intransa Inc. and EqualLogic Inc. In total, the company maintains 1.2 petabytes of storage, including 300TB of data backed up to tape and stored on tape silos.

The primary first-tier SAN production storage is provided by EMC Corp., IBM and Hitachi Data Systems Corp. Storage Technology Corp. and EMC's Clariion (CX700) fill in Tier 2. At the third tier, the company uses Sun (3510) and more EMC Clariion (CX400), and at Tier 4 are Intransa and EqualLogic.

More Complications

The NAS-based storage is the latest wrinkle in Nielsen Media's storage architecture. In August 2004, the company decided to expand its Florida data center, creating a consolidated data center to serve not only Nielsen Media but also other related VNU operations, such as NetRatings, which does Internet audience measurement and analysis.

The need to accommodate multiple operations further complicated the already complex NAS strategy. "NetRatings is a NetApp shop. Others use NFS and Solaris. Some do NAS from Windows," says Stevenson. Ultimately, all NAS will be rolled into the consolidated NAS strategy.

In addition, the organization supported about 190TB of DAS, most of it file-oriented. This, too, will be rolled into the consolidated NAS initiative as each server is phased out.

The consolidated NAS strategy consists primarily of two OnStor products: the OnStor SF4400, a 4U rack-mounted product with four Ethernet ports and four Fibre Channel ports, and the OnStor Bobcat, a 1U rack-mounted device with two Ethernet ports and two Fibre Channel ports. "We used the bigger OnStor at the second tier because it has more FC ports," explains Stevenson.

The company put the smaller and cheaper Bobcat, starting at $20,000, in the third tier. The Bobcat is billed as a NAS gateway that promises to scale from 1TB to 40,000TB (40 petabytes) using OnStor's virtualization capabilities. Within a cluster, all ONStor Bobcat NAS gateways share capacity that is provisioned from a single pool. It uses a 64-bit symmetrical multiprocessing pipelined architecture that employs high-speed network processors to move around the data. OnStor promotes the Bobcat for NAS consolidation.

Making the Bobcat particularly appealing to Nielsen is the extensive multivendor compatibility it offers. OnStor currently certifies compatibility with more than 100 storage devices and software applications from a variety of vendors, including IBM, EMC, StorageTek, HP/Compaq, 3PARdata Inc., Hitachi, Nexsan Technologies, Veritas Software Corp., IBM Tivoli, Symantec Corp. and McAfee Inc. "With OnStor, we're just getting the NAS head. That makes it easier to work with other storage vendors," says Stevenson.

Stevenson says deployment at Nielsen Media will be gradual, noting, "We'll bring up all new projects that require NAS with OnStor. The existing NAS will be migrated to OnStor at end-of-life."

Central Management Via SMI-S

Nielsen Media intends to manage the entire consolidated environment centrally, using SMI-S, starting with the Fibre Channel storage where it has deployed AppIQ. "The management of NAS involves the same level of complexity," says Stevenson. Eventually, it also will have to come under a standard management umbrella.

Backing up the consolidated NAS environment also presents challenges. Here Nielsen Media is looking at the Network Data Management Protocol. NDMP enables the backup and restore of NAS systems without the need for specialized software. It defines a standard for centralized backup that allows the backup application to control native backup-and-restore facilities on the NAS system regardless of the backup software package being used.

With NDMP, the data format on tape is consistent no matter which backup vendor is acting as the NDMP client. Currently, Nielsen Media intends to back up its data to its existing tape silos, although Stevenson is looking at virtual tape, a form of backup to disk.

While Stevenson doesn't label the resulting tiered storage environment "information life-cycle management," or ILM, Nielsen Media clearly is moving in that direction. It may, in fact, be there in everything but name. "We already analyze existing usage profiles and make decisions to move the storage through the different tiers. It is a continuous effort," he says. But whatever you might call it, it sounds a lot like ILM, and the company has been doing this for quite a while. "We're enabling what has already been going on," he adds.

By consolidating NAS and moving the NAS data through a highly scalable gateway to a SAN that contains multiple storage tiers, Nielsen Media is creating a storage infrastructure that will allow the company to both control costs and grow. From there, it will be in a position to implement ILM or grid storage or whatever other hot storage concept comes along that serves its needs.

Alan Radding is a business and technology writer. He can be reached at

Copyright © 2005 IDG Communications, Inc.

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