Terminology used in this appendix oracle help center. The ssa concept was developed by the ibm engineer ian judd in the early 1990s. Storage basics oftentimes, storage isnt given enough attention in system architecture, but it can make or. Serial attached scsi simple english wikipedia, the free. Key excerpts from scsi, sop, and pqi architecture models. Working draft project american national t101562d standard. The adaptec serial attached scsi 44300 card is a fourport controller with one x4 internal sff8484 connector featuring adaptec hostraid an integrated raid technology that maximizes system performance and uptime. Redundant storage enclosure processor sep implementation for use in serial attached scsi sas environment us14708,646 active us9361262b2 en 20060831. According to john taylor, programme manager at ibms storage division at havant, ssa will be used in arrays of discs.
A third type of storage solution exists that is a hybrid option called network attached storage nas. The adaptec 48300 supports up to eight direct attached drives and. In computing, serial attached scsi sas is a pointtopoint serial protocol that moves data to and from computer storage devices such as hard drives and tape drives. Adaptec serial attached scsi 44300 storage solutions. Ibm developed several ssa products, including disk enclosures. Interoperability testing was a key component of sas, because it increases the architectures flexibility by supporting both sas and sata disk drives and. Raid and raid controllers what is a controller card. Introduction to storage technologies and terminology. Todays predominant server storage interface standards rely on parallel transmission of data streams for devicelevel attachment. Sas physical links are a set of four wires used as two differential signal pairs. Find out information about serial storage architecture. Serial storage architecture ssa ibms proposed ansi standard for a standard highspeed interface to disk clusters and arrays.
Disk drives are installed in pairs, with each pair attached to the same loop. Serial attached scsi sas is a technology designed to move data to and from computer storage devices such as hard drives and tape drives. It is a pointtopoint serial protocol that replaces the parallel scsi. In computing, serial attached scsi sas is a pointtopoint serial protocol that moves data to and from computerstorage sas architecture consists of six layers. Ssa allows fullduplex packet multiplexed serial data. Mindshares sas architecture course provides a comprehensive understanding of the serial attached scsi interface. Ssa is an industry and user supported storage interface technology. Sas replaces the older parallel scsi parallel small computer system interface, usually pronounced scuzzy or sexy bus technology that first appeared in the mid1980s. The sas ssds support dualport operations and have improved reliability in. Serialattached scsi sas is an evolution of the parallel scsi device interface into a serial pointtopoint interface.
Sas also uses the scsi command set, but moves multiple bits of data one at a time. The ssa interface also supports fullduplex, so it can transmit and. Sas serial attached scsi is the latest storage interface thats gaining dominance in the. As you plan a storage system configuration, it is important to understand basic concepts about the construction of a server and the relationship between a storage system and the attached host systems. T10 committee scsi trade association current draft revision of sas2 from t10 6.
This includes the flow of data by using fibre channel, enterprise systems connection architecture escon, fibre connection ficon, small computer system interface scsi. In computing, serial attached scsi sas is a pointtopoint serial protocol that moves data to and from computerstorage. The universal enterprise storage connection by harry mason, director, industry marketing, lsi logic and president, scsi trade association trending toward serial the move to serially connected storage devices, primarily disk drives, is. Serial attached scsi sas is a computer bus used to move data to and from computer storage devices such as hard drives and tape drives. Us9361262b2 redundant storage enclosure processor sep. Arrays are composed of a group of disk drives that store data within the storage system. Serial storage architecture ssa was a serial transport protocol used to attach disk drives to server computers history.
The benefits of serial attached scsi sas for external. Factors such as larger capacity, density, security, scalability and accessibility, brought forward demand for storage devices that were more affordable than fibrechannel and more robust and reliable than sata. Serial attached scsi sas is an evolution of the parallel scsi device interface into a serial pointtopoint interface. Almost every form of data exchange you make on a daily basis can be broken down into three groups. Storage basics oftentimes, storage isnt given enough attention in system architecture, but it can make or break the service level agreement sla for your application response times.
Knowing about serial advanced technology attachment sata, scsi and serial attached scsi sas is an important factor in designing a costeffective storage environment. Abbreviated as ssa, serial storage architecture is an open industrystandard interface that provides a highperformance, serial interconnect technology used to connect disk devices and host adapters. Sas serial attached scsi is the latest storage interface thats gaining dominance in the server and storage market. Knowing about serial advanced technology attachment sata, scsi and serialattached scsi sas is an important factor in designing a costeffective.
Scsi first appeared in the mid 1980s in corporate data centers. Serial ata will be implemented in desktop pcs and lowcost, nonmissioncritical server storage solutions. The ssa standard can be an alternative to scsi small computer system interface in growing environments where scsi no longer. In computing, serial attached scsi sas is a pointtopoint serial protocol that moves data to and from computerstorage devices such as hard drives and tape drives. The answer comes in the form of serial attached scsi, which will have the capability of fulfilling these requirements as. This solution uses a dedicated server or appliance to serve the storage array. Serial storage architecture ssa is an open protocol used to facilitate highspeed data transfer between disks, clusters, and servers. Ssa serializes the scsi data set and using loop architecture that requires only two wires. Kembel a comprehensive guide to serial attached scsi sas inc. Sas is widely considered to be the prevalent interface for direct attached storage and is used to support hard drive controllers in enterprisegrade server farms. You might have heard of sata hard disks parallel ata earlier in your laptop computer. Ssa devices are logically scsi devices and conform to all of the scsi command protocols.
A format for storage or transmission of binary data in which the. Ssa allows fullduplex packet multiplexed serial data transfers at rates of 20mbsec in each direction. He has participated actively in scsi standards development for 22 years and served as technical team leader for the serial attached scsi sas working group as it developed the proposal that served as the basis for the sas standard project. Ibms proposed ansi standard for a standard highspeed interface to disk clusters and arrays.
Serial attached scsi sas solid state drives for efficiency. Pointtopoint architecture that enables each device to connect directly to a port with dedicated bandwidth, rather than having a number of devices share a common bus. Key excerpts from scsi, sop, and pqi architecture models scsi initiator device. Sas is an evolution of parallel scsi to a pointtopoint serial interface. Serial attached scsi sas solid state drives ssds provide a faster data transfer rate than a serial advanced technology attachment sata ssd.
The standard is designed especially for networks, but can be used with smaller personal systems as well. The ds8800 contains large capacity serial attach scsi sas drives connected using fibre channel adapters. Serial attached scsi mindshare technology series series by mike jackson. A note on server storage sas serial attached scsi, sas. Working draft project american national t101562d standard revision 5 9 july 2003 information technology serial attached scsi sas this is an internal working document of t10, a technical committee of accredited standards committee incits international committee for information technology standards. Mar 24, 2015 serial attached scsi is said to offer an ideal solution for businesses with substantial storage, backup and archiving demands. Serial storage architecture ssa is an open standard for highspeed access to highcapacity disk storage. Isoiec fcd jtc 1 n 14776412 6 isoiec isoiec jtc 1 n 14776412 scsi architecture model 2 sam 2 revision i25 figures page 1 requirements precedence 9. Universal serial bus usb usb attached scsi uas infiniband. Raid redundant array of inexpensive disks is a data storage structure that allows a data center to combine two or more physical storage devices hdds, ssds, or both into a logical unit that is seen by the attached system as a single drive. Sas serial attached scsi is the latest storage interface thats gaining.
Serial attached scsi sas today todays varied server applications necessitate a variety of storage requirements. Sas can be seen as a merged scsi and sata interface, since it still uses scsi commands yet it is pincompatible with sata. And for many years this web address youre seeing now was the home page for sas news. Sas serial attached scsi is the serial storage interface that has been designed to. Sas and scsi express marty czekalski president, scsi trade. Serial attached scsi sas is a storage interconnect fabric that connects the enterprise hard drives ssds with the server motherboard. Adaptec serial attached scsi 48300 storage solutions. All the components in a typical ssa subsystem are connected by bidirectional cabling. The adaptec 48300 supports up to eight direct attached drives and up to 128 drives using expander technology. Serial attached scsi serial attached scsi is the latest generation of this enterprise storage connect and promises to greatly expand upon the existing capabilities of parallel scsi. One differential signal transmits in one direction while the other differential signal transmits in the opposite direction.
Serial attached scsi will be implemented in enterprise class devices providing the full functionality of scsi hard disk drives hdds. Sas expanders and wide ports sas wide ports are a unique feature in data storage. Pcs and lowcost, nonmissioncritical server storage solutions. Ssa provides data protection for critical applications by helping to ensure that a single cable failure will not prevent access to data. Well start with a brief description of the major storage networking variations. Introduction to serial attached scsi interface sas. Serial storage architecture article about serial storage. Introduction to serial attached scsi sas parallel scsi. The adaptec serial attached scsi 48300 card is an eightport controller featuring adaptec hostraid an integrated raid technology that maximizes system performance and uptime.
Minisas are designed to signifi cantly reduce the cable size for storage systems currently using sas 4lane 4x or 4lanes of data. Server storage solutionswhite paper serial attached scsi sas, the followon to parallel scsi, is designed for highperformance enterprise requirements and offers both the benefits of backward compatibility with scsi and interoperability with serial ata sata, bringing enterprises a flexibility and cost savings previously not possible. The adaptec 44300 supports up to four direct attached drives or up to 128 devices using expander technology. Serial storage architecture list of device bandwidths usb attached scsi scsi. The io protocol most prevalent in the midrange world. Mini serial attached scsi minisas internal cable assemblies. S ome applications are more focused on transaction processing performance, while others are more concerned with lowcost, high availability or the ability to scale the system. Sas serial attached scsi let mindshare bring sas to life for you mindshares sas architecture course provides a comprehensive understanding of the serial attached scsi interface.
Sas links end devices through directattach connections, or through expander devices. Redundant storage enclosure processor sep implementation for use in serial attached scsi sas environment. It is an ideal interconnect solution for the growing server and storage market. A controller card is a device that sits between the host system and the storage system, and allows the two systems to communicate with each other. The course covers all aspects of the standard, primarily from a hardware perspective, and compares the usage model of sas with other enterprise interface designs.
Serial attached scsi timeline from storage history. Parallel scsi moves multiple bits of data in parallel at the same time, using the scsi command set. Serial attached scsi intends to leverage the 20 years of proven scsi legacy middlewaresoftware that is entrenched in the enterprise, as well as deliver a. Dongguan shuangyi electronic technology manufacturing co. Mr lohmeyer obtained his bs in electrical engineering from purdue university. Serial ata and serial attached scsi technologies technology brief. Sas serial attached scsi is the serial storage interface that has been designed to replace and upgrade scsi, by far the most popular storage interface for.
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