IBM is bidding to expand its share of the storage market with a low-end Windows and Linux server storage system that has large system, Unix-server style capacities.IBM is bidding to expand its share of the storage market with a low-end Windows and Linux server storage system that has large system, Unix-server style capacities.
In the growing competition to meet rapidly increasing storage needs, IBMs move may represent the type of storage units soon to come from competitors EMC, Hewlett-Packard and Sun Microsystems. Dave Walling, vice president of marketing for IBM storage systems, termed the newly launched ProFibre Storage Array DF4000R as "RAID for NT." It is actually aimed at Windows NT/2000, Linux and low-end Unix systems.
The DF4000R is an array of hard drives that can be configured to meet a range of Redundant Array of Independent Disks requirements, from minimal redundancy and backup to full RAID 5 requirements, with data mirrored in a real-time duplicate set. RAID units replaced high volume, single unit disk drives designed for mainframes and large servers with multiple PC component drives that can back each other up and weed out a failed drive.
Instead of being a stand-alone, server attached device, the DF4000R is equipped with Fibre Channel-based controllers that allow it to be plugged into a high-speed Fibre Channel storage area network. Many storage devices may be linked on the network to multiple servers or remote servers. Fibre Channel is a standard for storage area networks that can operate at data transmission speeds of 2 gigabytes per second.
IBMs RAID unit will be priced in the $25,000-to-$30,000 range, compared with $100,000 or more for a Unix storage unit with similar capacities, Walling said. The DF4000R can move data at a sustained 350 megabytes per second, manage 100,000 transactions per second and hold up to 1.1 terabytes of data. The unit contains 15 disks, each holding 73 gigabytes.
The vibration set up by the platters of so many high-speed spinning disks prompted an advanced enclosure design. Although it looks like the sheet metal of other RAID units, the enclosure is actually made from a sandwich of two metal sheets with a plastic material in between. When dropped on a hard surface, a sample of the material provided by IBM makes a flat noise with little bounce. If an equal thickness of regular sheet metal were dropped, it would bounce with a clang, indicating a higher level of vibration from the blow.
The vibration dampening is important, said Walling, because build up of vibration in RAID arrays leads to diminished performance. The disk drives are not failing, but the vibration makes it harder for the tracking device on the disk drive head to know exactly where it is over the spinning platter. If vibration interferes with the head placement, the device waits for the platter to make another revolution before identifying the track it is about to read, he said.
The vibration problem is likely to escalate in the next generation of RAID arrays because platter speeds will move from 10,000 revolutions per minute to 15,000, according to Walling. And, the DF4000R can dampen vibration equivalent "to a door being shut hard, an elevator going up or down or a minor earthquake," he said.
IBMs DF4000R can be equipped as a dual RAID controller storage unit. The controller manages the data traffic flow to and from disks. If one controller fails, the other will take over its tasks. The dual controllers are backed up by other redundant components, such as the power supply, to minimize the possibility of failure, said Walling.
The DF4000R is currently aimed at original equipment server and storage manufacturers, although Walling didnt rule out its appearance within the IBM product line, such as the xServer, formerly known as the Netfinity line based on Intel processors.
The storage unit is a rack mount device for use in cramped data centers or Internet colocation services. The sleds, or sliding drawers, that hold a server or RAID device in the rack have shock feet, or a cushion, to also dampen vibration, noted Michael Joyce, product manager.
Eight of the 3u or three units of rack mount space (about 5.25 inches) can be daisy-chained together to produce an 8.8 terabyte unit managed as a single storage device, said Joyce.
The DF4000R is available immediately and is built on Mylex FFx-2 RAID controllers. IBM acquired Mylex for $200 million September 1999. At the time, Mylex was regarded as the leader in low-end RAID controllers, Walling said.
Data Storage, Data Backup and Storage Virtualization 
