Appendix A: Introduction to SAS ● 58

Terminology Used in This Appendix

For convenience, SAS HostRAID controllers are referred to generically in this appendix as SAS controllers, HBAs, disk drives, and external disk drive enclosures are referred to as end devices and expanders are referred to as expander devices.

For convenience, this chapter refers to end devices and expander devices collectively as SAS devices.

What is SAS?

Legacy parallel SCSI is an interface that lets devices such as computers and disk drives communicate with each other. Parallel SCSI moves multiple bits of data in parallel, using the SCSI command set.

SAS is an evolution of parallel SCSI to a point-to-point serial interface. SAS also uses the SCSI command set, but moves multiple bits of data one at a time. SAS links end devices through direct-attach connections, or through expander devices.

SAS controllers can typically support up to 128 end devices and can communicate with both SAS and SATA devices. You can add 128 end devices or even more with the use of SAS expanders. For more information, see SAS Expander Connections on page 61.

Although you can use both SAS and SATA disk drives in the same SAS domain, Adaptec recommends that you not combine SAS and SATA disk drives within the same array or logical drive. The difference in performance between the two types of disk drives may adversely affect the performance of the array.

Data can move in both directions simultaneously across a SAS connection (called a link—see next section). Link speed is 600 MB/sec in full-duplex mode. A SAS controller with eight links has a maximum bandwidth of 4800 MB/sec in full-duplex mode.

Although they share the SCSI command set, SAS is conceptually different from parallel SCSI physically, and has its own types of connectors, cables, connection options, and terminology, as described in the rest of this chapter.

To compare SAS to parallel SCSI, see page 62.

Page 60 Page 62
Page 61
Image 61
Adaptec 1225SA, 58300, 44300, 48300, 1220SA, 1420SA, 1430SA manual Terminology Used in This Appendix, What is SAS?
Page 60 Page 62

1430SA, 1225SA, 1420SA, 1220SA, 48300 specifications

Adaptec, a prominent name in the world of storage solutions, offers a diverse array of RAID controller cards aimed at enhancing data storage and management in both consumer and enterprise markets. Among its acclaimed products are the Adaptec 1220SA, 1430SA, 44300, 1225SA, and 1420SA. These cards ensure increased data protection, improved performance, and greater scalability.

The Adaptec 1220SA is a robust SATA RAID controller designed for small to medium-sized businesses. It supports RAID levels 0, 1, 1E, 5, and 10, providing flexibility for users to optimize data redundancy and performance. With the capability of handling up to four SATA drives, it guarantees an efficient and reliable setup while minimizing potential data loss. The controller also features an intuitive web-based management interface, making it easier to administer and configure.

The Adaptec 1430SA extends similar functionality with enhanced features. It is designed to accommodate up to eight SATA drives and supports the latest 3 Gbps SATA technology. This model includes optional battery backup for preserving critical data during unexpected power outages, ensuring that users maintain data integrity and protection at all times.

In the enterprise domain, the Adaptec 44300 shines as a high-performance RAID controller. It offers support for 12 SATA drives, which allows for expansive storage scalability, crucial for data-intensive applications. The advanced RAID features include support for RAID 6, providing dual parity data protection. The controller is built with a powerful processor and memory, allowing for faster data processing and enhanced throughput.

The Adaptec 1225SA is another noteworthy model. Designed for entry-level RAID applications, it offers a balanced combination of performance and reliability. Supporting up to four SATA drives, the 1225SA is particularly well-suited for environments where uptime is critical, delivering functionalities such as hot-swapping. This feature allows users to replace failed drives without shutting down the system, significantly reducing downtime.

Lastly, the Adaptec 1420SA caters to users who require a cost-effective but reliable storage solution. With support for RAID 0, 1, and JBOD, it is a versatile option for enthusiasts and small businesses. The controller can manage up to two SATA drives, making it ideal for basic applications where simplicity and efficiency are paramount.

Collectively, these Adaptec controllers showcase cutting-edge RAID technology and storage management features, reinforcing their position as reliable options for users ranging from home users to enterprise-level organizations seeking optimal data storage solutions.
Top Page Image Contents