HP To Shift to 2.5-inch Disk Drives

Within the next year, Hewlett-Packard (NYSE: HPQ) will shift its entire line of ProLiant servers and storage to 2.5-inch, 10K RPM disk drives, the company said yesterday.

The small form factor (SFF) drives offer several benefits over the 3.5-inch disks in common use today. The smaller drives are denser, allowing for more storage in a smaller space and more hard drives within a single machine. Because they are smaller and their cables are smaller, they also allow increased air flow and, thus, ease the ability to cool the system while using less power.

Serial Attached SCSI

The drives run on serial attached SCSI (SAS) interfaces, which have data transfer rates in excess of 3 gigabits per second (Gbps) and can reach transfer rates of more than 10 Gbps. SAS is compatible with the competing hardware interface, SATA (serial advanced technology attachment).

SAS is backward compatible with parallel SCSI, which means that enterprises can continue to use the same storage management and enterprise application software to control their storage.

SAS also offers exponential growth in scalability. The limit for SCSI drives on a shared 320-Mbps bus is 14; with SAS, that number jumps to 128 drives per bus. HP will also offer 3.5-inch, 15K RPM models.

The technology was developed with drive vendors Fujitsu, Hitachi (NYSE: HIT) and Seagate.

"The move to small form factor is not inevitable, but it makes a lot of sense," analyst David Freund of Illuminata, told TechNewsWorld.

Freund said that the quality of the disks degrade as you get closer to the edges and scanning that large of a space for data takes too long. Therefore, manufacturers "short stroke," or prevent the technology from reading all the way to the edge of the 3.5-inch disk, creating de facto 2.5-inch drives.

Ahead of the Pack

HP is trying to get out in front of storage providers EMC (NYSE: EMC) and IBM (NYSE: IBM) by releasing the first SFF drives in May for ProLiant servers. HP will continue to roll out products incorporating the new architecture in the BladeSystem, Integrity and StorageWorks lines after that, with the final products out by June 2006, according to Paul Perez, HP vice president of storage, networking and infrastructure, ProLiant division.

IBM offers 2.5-inch drives in its the eServer x366, but they use parallel SCSI technology, which transfers data much more slowly. HP ships more than 1 million hard disk drives per quarter and that the new technology could push that number higher.