Seagate Technology is now the second hard drive manufacturer to announce a 3.5-inch hard drive with a 2TB capacity. Western Digital got the honor of being the first to announce its 2TB drive last week, the WD Caviar Green
(WD20EADS) SATA drive. Seagate's 2TB drive is actually part of a new family of enterprise-class hard drives called Constellation.
The new hard drive family consists of 2.5-inch Constellation drives in 160GB and 500GB capacities, and 3.5-inch Constellation ES drives in 500GB, 1TB, and 2TB capacities. All of the new drives, except for the 2.5-inch 160GB model, will be available in both SATA and SAS 2.0 interface versions. (The 2.5-inch 160GB drive will only be available with a SATA interface; Seagate considers this drive a good choice for "boot/entry server applications
.") SAS 2.0 is fairly recent update to the Serial Attached SCSI protocol. SAS 2.0 offers a number of significant improvements over SAS and SATA, such as a 6Gb per second transfer rate, multiplexing, zoning, and even support for up to 10-meter cable lengths. (For a good overview of SAS 2.0, you can read PMC-Sierra's white paper (PDF) here
Seagate regards the Constellation family as "nearline
" drives, which Seagate positions as ideal for "tier-2
" enterprise storage applications. Storage Advisors' Tom Treadway provides an excellent detailed explanation of what Seagate's definition of nearline drives is here
. A brief overview of this definition is that nearline drives are meant to be always-on, high-capacity, low-cost drives with a high reliability--but not necessarily as fast or expensive as tier-1 enterprise-level drives. Nearline drives typically have a high mean-time-before failure (MTBF), a higher rotational vibration (RV) tolerance, include built-in error correction, integrated error recovery, include workload management, built-in power management, microcode download support, and include support for the Write Same command.
The entire Constellation family also supports Seagate's optional, self-encrypting drive (SED) technology, which Seagate claims provides "government-grade data security through the drive's life cycle
" as well as even after the drives are retired. The new drives also utilize power-saving technology, which Seagate claims "decreases power consumption by up to 54% for record power savings in enterprise environments
.""With Seagate's innovative PowerChoice technology, both Constellation hard drive models deliver the highest power-reduction savings ever offered in an enterprise-class HDD, and provide flexible, user-manageable options to deliver power savings without sacrificing performance, data integrity, or reliability. In addition, the Constellation family of drives are backed with field-proven, enterprise-grade reliability and rated at a full 1.2 million hours MTBF."
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.