HP looks to use 2.5-in. drives in servers, arrays

Computerworld - Hewlett-Packard Co. plans to start shipping 2.5-in. disk drives with enterprise-class features in its ProLiant servers next year and later will add the space-saving technology to its disk subsystems and arrays.

Fujitsu Computer Products of America Inc. yesterday announced that HP has started testing its 2.5-in. drives, which use the Serial Attached SCSI interconnect and support data transfer rates of up to 300MB/sec. In addition, Seagate Technology LLC said it will deliver 2.5-in. drives to HP and other vendors during the first half of 2004.

HP will be able to put three of the new drives in the same amount of space that's now occupied by one 3.5-in. model, said Jeff Jenkins, the company's vice president of server storage and infrastructure. That should let HP increase storage capacity and data throughput in servers, disk arrays and other non-PC devices while reducing the size of the boxes, he said.

The 2.5-in. technology is expected to debut in the ProLiant line in the second half of 2004, according to Jenkins. HP then plans to roll out multiple-disk enclosures and modular arrays using the smaller drives in 2005 and 2006, respectively, he said.

Dave Reinsel, an analyst at market research firm IDC, said HP is the most aggressive adopter of 2.5-in. drives among makers of enterprise servers and storage devices. Reinsel said hardware vendors could reduce by two-thirds the space required for disk drives in blade servers or rack-mounted systems by switching to 2.5-in. units.

The support for Serial Attached SCSI is another potential advantage of the Fujitsu drives HP is testing. The serial SCSI standard uses a point-to-point connection for each drive in an array. That's designed to be more scalable than the master/slave architecture employed by the parallel SCSI technology that's prevalent now, Reinsel said. With parallel interfaces, a single controller must be shared by all the drives on a bus.

The 2.5-in. drives that HP plans to use also can be mixed with lower-cost Serial Advanced Technology Attachment drives inside storage systems, said Mike Chenery, vice president of advanced engineering at Fujitsu Computer Products in San Jose. Combining the two kinds of drives would enable users to do backups of their transactional data within the same box.

"Instead of one drive, you can put in two or three drives and enable RAID functionality in a 1U- or 2U-high server, which would be impossible with a 3.5-in. drive due to the heat and cooling requirements of these new microprocessors," Chenery said. (A U is a unit of measurement for server racks; 1U has a height of 1.75 in.)

The 2.5-in. drives are hot-swappable and have dual ports for redundancy, and they initially will be sold in 36GB and 73GB models, Chenery added.

However, 2.5-in. drives have a long way to go to overtake their 3.5-in. SCSI counterparts as the top storage technology for corporate servers and disk subsystems. Reinsel said 3.5-in. SCSI drives currently account for 78% of the enterprise-class disk drive market, with the remainder taken by Fibre Channel technology. He predicted that 2.5-in. serial SCSI drives should grab about 2% of the market next year, with that share growing to 10% by 2006.

"The advantage of 2.5-in. drives most immediately will be in the internal server storage market," Reinsel said. "It'll be a fairly gradual thing. You have a huge installed base of 3.5-in. slots out there."