Storage Aggregation: When the Sum Is Less Than the Parts

One of the biggest storage problems companies face is that as storage demands grow, managing storage becomes increasingly difficult. You can address the increasing storage needs by buying ever larger storage assets, but this approach requires that you forecast eventual needs and purchase equipment accordingly. And it doesn't solve the storage management issues. Using a different approach, you can virtualize existing storage assets and turn multiple storage systems into a single managed asset. Several companies offer virtualization products, including the VersaStor initiative (Compaq), which puts management intelligence into host bus adapters, and the SANsymphony technology (DataCore), which creates a centralized Windows NT Server console.

Last week, Tricord introduced a new aggregation technology called Illumina. Tricord's Illumina software, first implemented on a Network Attached Storage (NAS) device called the Lunar Flare server appliance, virtualizes NAS devices into a single managed unit. But it does more than that. When you combine several 1U (1.75") Lunar Flares in a rack-mounted panel, the software combines the storage into a single RAID 5-like unit—the NAS devices themselves are the redundant systems. That is, Illumina turns a NAS device into the equivalent of a drive in a RAID configuration. If a Lunar Flare loses system power, the system continues working from the redundant information written on the other NAS devices. The Illumina software polls the system to see whether the error is temporary or permanent. After a while, the software starts to rebuild the RAID 5-like configuration to a hot-spare NAS device. You can think of this as a NAS cluster, a feature you currently find only at the high end of the storage appliance space.

Using Illumina's first shipping version, you can create a 16-node NAS cluster. Each Lunar Flare in the cluster can contain up to 135GB of raw storage for a total capacity of about 1.7TB (reserving three Lunar Flares as hot spares). Illumina supports Windows Common Internet File System (CIFS) and Windows clients such as Windows 2000, Windows NT, and Windows 9x. Illumina also provides SAMBA support for UNIX clients on a Windows network. You manage clusters with a Java browser-based utility, which provides event logging and email notification about problems.

The demo I saw was compelling, and Illumina will offer good value to shops that build their storage assets using NAS. Tricord tells me that the Illumina software will find expression in many other types of storage applications, but the company is counting on this extra high availability and virtualization feature to compete with devices such as the Quantum Snap Server (and its Dell rebranded cousin), which has neither feature.

Tricord's release of Illumina is the culmination of a 3-year development project based on a DFS begun at the California Institute of Technology with input from IBM. Tricord chose to work on the technology when the company left the high-end PC server marketplace, which players such as Compaq increasingly dominated.

Tricord expects to sell the Illumina NAS server appliance clusters as back-end storage appliances for email, database, and multimedia—and as server application appliances for Web servers, backup servers, and Web content/distribution servers. Tricord will sell directly to end users and to ISPs and application service providers (ASPs). The company will also work with partners to service those markets and target specific named accounts. Other products based on this technology will be forthcoming.

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