Definition

Serial Attached SCSI (SAS) is the logical evolution of SCSI that satisfies the enterprise data center requirement for scalability, performance, reliability and manageability, while leveraging a common electrical and physical interface with Serial ATA (SATA). This compatibility provides users with unprecedented choices for server and storage subsystem deployment.

Serial Attached SCSI vs traditional SCSI

SAS was developed to address I/O and direct attach storage requirements that traditional SCSI cannot meet. It provides universal interconnect with SATA, while offering logical SCSI compatibility along with SCSI reliability, performance and manageability.

1. Why was Serial Attached SCSI developed?

SAS was developed to address I/O and direct attach storage requirements that traditional SCSI cannot meet. It provides universal interconnect with SATA, while offering logical SCSI compatibility along with SCSI reliability, performance and manageability.

2. How will Serial Attached SCSI benefit the storage industry?

SAS leverages the proven SCSI technologies that customers expect in data center environments, providing robust solutions and generational consistency. It is based on a serial interface, allowing for increased device support and bandwidth scalability, as well as reducing the overhead impact that challenges today's SCSI storage environments. It utilizes SATA development work on smaller cable connectors, providing customers a downstream compatibility with desktop class ATA technologies.

Simplified routing enables a new generation of dense devices such as small form factor (SFF) hard drives, permitting storage solutions to scale externally.

3. What are the end-user benefits of Serial Attached SCSI?

Key end-user benefits include enterprise class robustness, investment protection in compatible SCSI software and middleware and the choice of direct-attach storage devices (SAS or SATA) in a single SAS system. In addition, longer cabling distances, smaller form factors and greater addressability will lead to a new level of flexibility when deploying mainstream data-center servers and subsystems. SAS is based on the foundation of the industry-leading SCSI specification and as a result, reliability, familiarity and peace of mind will satisfy user's needs for continuity in the data center.

4. What are the estimated costs of Serial Attached SCSI solutions?

It is anticipated that SAS solutions will not exceed current SCSI pricing.

5. Are Serial Attached SCSI connectors compatible with those of SCSI server and storage solutions?

No, they are not compatible, as SAS connectors are much smaller than SCSI connectors.

6. Is Serial Attached SCSI complementary to Serial ATA?

SAS complements SATA by adding dual porting, full duplex and device addressing, plus it offers higher reliability, performance and data availability services, as well as logical SCSI compatibility. STA will continue to enhance these metrics as the specification evolves, including increased device support and longer cabling distances. SATA is targeted to cost-sensitive non-mission-critical desktop storage environments. Most importantly, SAS and SATA are complementary technologies based on a universal interconnect, where SAS customers can choose to deploy cost-effective SATA drives in a SAS storage environment.

7. Can I use Serial Attached SCSI hard drives in my Serial ATA workstation or desktop PC?

While not native, SAS hard drives can be used on SATA desktops and workstations by adding a host bus adapter.

Netstor's SAS Solution