SAN JOSE, Calif. — An industry group is releasing its first specification on Monday (Sept. 25) to bring standards to the rapidly growing market for hard-disk drive arrays.

In addition, IBM and Network Appliance are joining Dell, EMC, Intel, LSI Logic and Seagate Technology as part of the Storage Bridge Bay (SBB) alliance.

The effort is one of many to define a new class of modular storage arrays that are easy to use and expand as businesses grow. IBM and NEC will roll out new proprietary modular arrays soon. Sun Microsystems announced a novel product earlier this year.

The overarching trend is to help business pack more data on purpose-built storage networks while using less money, space, heat and power. Increasingly, systems makers see their differentiation in software to manage those networks, rather than the hardware package.

"You will see a bifurcation where proprietary elements are pushed down into the building blocks, and the systems makers value add is in the software," said Barry Rudolph, vice president of systems storage at IBM in an interview at the recent Diskcon conference.

"We are trying to standardize parts of the storage enclosure that are ready for it, to speed time to market and reduce proprietary differences that don't add value," said Bill Dawkins, chair of SBB and a storage strategist at Dell.

The SBB spec "is a hardware standard that raises the bar on reliability and helps the hardware become more mature. The value is in the software, services and interoperability and testing," Dawkins added.

"They are making a bet that the differentiation in housing for storage drive arrays is not very big," said John McArthur, a systems analyst at International Data Corp. (Framingham, Mass.)

Not everyone sees the need for the new spec. Two top tier array makers, Hewlett-Packard and Hitachi Data Systems, are so far not taking part. "It's an interesting effort for Dell and EMC, but we already have all the packaging and cost reduction we need today," said Abbott Schindler, a senior storage technologist at HP.

The SBB spec, now available free on the group's Web site, defines a 8.1- by 10.8- by 1.36-inch "canister" for an array's controller electronics and a passive backplane that connects it with up to 28 drives using Fibre Channel, SAS or Serial ATA interfaces. The spec also defines how to power, cool and manage the canister.

The standard is agnostic about the type of chassis or its interface to a network. Similarly, it is geared to enable a wide range of systems from RAID arrays to virtual tape libraries. Although similar to the Advanced TCA effort focused on telecom systems, the SBB design required different mechanical and electrical properties tailored for storage.

A version 2.0 of the SBB spec will increase the power budget of the canister from 100W to 200W or more. It will also expand the number of drives the backplane can handle, although a new limit has yet to be set. The existing backplane has undefined pins that could accommodate up to another 12 drives.

The version 2.0 spec will also define a chassis for the canisters and open the door to faster internal interconnects in the works including the pending 5Gbit/s version of PCI Express and 6Gbit/s version of Serial-attached SCSI. The SBB revision may not be available until mid-2007, depending in part on when details of the new versions for Express and SAS are ratified.

The initial SBB spec "lets people use high speed interconnects as they come out. But we can't nail down the latest interfaces until their specs are completed," Dawkins said.

"You'll see a lot of products around this first spec," he added.

Dell already ships a system based on an early version of the first spec. The Dell PowerVault MD1000 is a chassis with 15 SAS or SATA drives in a JBOD arrangement that can be clustered with up to three boxes for a total of 45 drives.

The SBB effort targets the sweet spot for arrays that range in cost from about $5,000 to $100,000, said Dawkins.

"This is focused on the lion's share of the market for arrays," said McArthur of IDC. "It will certainly address the lion's share of what Dell ships and a lot of what EMC ships, too," he added.

Rack 'em up

Several more shoes have yet to fall in the move to modular arrays.

In July, Sun announced its novel Sun Fire X4500, a two-processor data server that packages 48 drives with up to 24 terabytes of data in a 4U system. Sun's Andy Bechtolsheim pitched the system as a video server or for applications that need number crunching on large amounts of data, rather than a standalone array.

Separately, NEC is developing a storage array that will be able to scale from the current entry-level product with about 15 drives to its largest system with more than 1,200 and beyond. The new array is based on a proprietary crossbar interconnect and will ship sometime in 2007.

A fully configured array could have as many as 3,000 drives and a terabyte of cache, and would likely be designed for Fibre Channel based storage area networks. The crossbar switch at the heart of the modular system has its heritage in NEC's telecommunications products.

"We are embracing in one product something that extends from our smallest small-business offerings to our largest monolithic arrays," said Victor Gamaly, a senior product marketing manager for the storage business in NEC Corp. of America.

Earlier this month, IBM tipped word that it will ship a product this fall roughly based on its Ice Cube R&D project that aimed to build a 32 Tbyte array out of modular "bricks" consisting of 12 2.5-inch hard drives in a novel interconnect scheme. The specs and even the business model for the project have changed since it was originally detailed, said one researcher close to the product, but as the name suggests its cooling scheme is one of its unique attributes.

"There's a lot going on in modular arrays as building blocks, and you'll see more," said Rudolph of IBM. "Everything will become more modular either physically or virtually. The question becomes at what point are the modular building blocks better than a proprietary design?" he added

Like Sun, HP has shown ways of packing its server blade chassis with hard drives as one route to a modular array. Separately, the company already ships modular systems that can embrace as much as 100 Tbytes, said Schindler of HP.

He sees the market for modular arrays split into two kinds of systems. One will use general-purpose controllers such as the x86 that offer lower cost but higher latency. Those systems will lack the capacity and performance of larger, also expandable arrays using proprietary controllers, he said.

Separately startups including 3Par and Panasas, both based in Fremont, Calif., have been trying to pioneer new directions for modular storage arrays.