Dual-Port SAS Drives are a Boon to IT
The new serial interfaces, Serial Attached SCSI (SAS) and Serial ATA (SATA), have been designed to replace their parallel predecessors. They will
support faster data transfer rates and more devices per controller, as well as reduce the size and complexity of the cables and connectors (thus
enabling smaller, more densely-packed disk arrays). System builders will also be able to integrate SAS and SATA hard drives in a single enclosure.
SAS goes beyond SATA by adding dual porting, full duplex, device addressing and it offers higher reliability, performance and data availability
services, as well as logical SCSI compatibility. It will continue to enhance these metrics as the specification evolves, including increased device
support and longer cabling distances.
SAS re l iabi l i ty
For customers requiring the highest levels of reliability and perfor-
mance in mission-critical server environments, SAS hard drives will
offer the highest performance and reliability. This is due, in part, to
the dual-port attributes of the SAS interface.
SAS hard drives are designed to withstand the demands of high duty
cycle enterprise storage applications. The dedicated, point-to-point
SAS architecture provides reliable connectivity and full bandwidth to
each drive. Dual porting provides two separate data paths, allowing for higher levels of performance and eliminating single points of failure.
The support for redundant connections enabled by the dual port feature is one of several key differentiators between SAS and SATA drives. It is
one of the reasons that SAS drives are well suited for use in highly available enterprise storage environments.
In parallel architectures, multiple initiators have traditionally been used to provide hard drive access to multiple hosts and host bus adapters.
The multiple initiator approach however, can result in single points of failure that can prevent drive access.
The dual-port characteristics of SAS add