Seagate Technology LLC on Monday unveiled its Constellation family of enterprise hard drives that features 2.5-inch and ES 3.5-inch drives with capacities of up to 2.0 TB as part of a new family of near-line SAS and SATA drives.

The drives come in Serial Attached SCSI 6Gbit/sec. or Serial ATA 3Gbit/sec. models, and include a feature that allows them to shut down when not in use to save power. It has four-platter drives rotating at 7,200 rpm. They come with 32MB cache on the SATA model and 16MB cache on the SAS model and will replace Seagate's Barracuda ES enterprise drives.

The drive can be set to enter the various power-saving levels after or for definable periods. The Barracuda desktop drive remains available. Seagate is also positioning the Constellation products as data centre storage array drives.

Recently, Western Digital's WD released a Caviar Green hard-drive family featuring 2.0-TB capacities. It was a SATA drive aimed at desktop and external storage applications. WD's 2TB drive uses four 500GB platters, each of which has 400Gbit-per-square-inch areal density with a transfer rate of 3Gbit/sec and a 32MB cache at a suggested retail price of $299. WD got the honor of being the first to announce its 2TB drive.

Seagate has not announced pricing yet for any of the new drives, but the 2.5-inch Constellation drives should ship sometime this quarter, and the 3.5-inch Constellation ES drives are scheduled to ship in the third quarter of 2009.