![]() For a SAS expander device, the SCSI port identifier and SCSI device name are the same SAS address. People sometimes call a SAS address a World Wide Name or WWN, because it is essentially the same thing as a WWN in Fibre Channel. People sometimes refer to a SCSI port identifier as the SAS address of a device, out of confusion. In SAS, both SCSI port identifiers and SCSI device names take the form of a SAS address, which is a 64 bit value, normally in the NAA IEEE Registered format. In Fibre Channel, the port identifier is a WWPN and the device name is a WWNN. One does not often see these device names because the port identifiers tend to identify the device sufficiently.įor comparison, in parallel SCSI, the SCSI ID is the port identifier and device name. In addition, every SAS device has a SCSI device name, which identifies the SAS device uniquely in the world. SAS devices use these port identifiers to address communications to each other. It is assigned by the device manufacturer, like an Ethernet device's MAC address, and is typically worldwide unique as well. Each SAS port in a SAS domain has a SCSI port identifier that identifies the port uniquely within the SAS domain, the World Wide Name. SAS-5: 45 Gbit/s development started 2018 Ī SAS Domain is the SAS version of a SCSI domain-it consists of a set of SAS devices that communicate with one another by means of a service delivery subsystem.SAS-4: 22.5 Gbit/s called "24G", standard completed in 2017.SAS-3: 12.0 Gbit/s, available since March 2013.SAS-2: 6.0 Gbit/s, available since February 2009.Expanders facilitate the connection of multiple SAS End devices to a single initiator port. Expanders: devices that form part of a service delivery subsystem and facilitate communication between SAS devices.Typically cables connecting an initiator and target with or without expanders and backplanes constitute a service delivery subsystem. A service delivery subsystem: the part of an I/O system that transmits information between an initiator and a target.A target device could be a hard disk drive or a disk array system. A target: a device containing logical units and target ports that receives device service and task management requests for processing and sends responses for the same requests to initiator devices.Initiators may be provided as an on-board component on the motherboard (as is the case with many server-oriented motherboards) or as an add-on host bus adapter. An initiator: a device that originates device-service and task-management requests for processing by a target device and receives responses for the same requests from other target devices.Introduction Storage servers housing 24 SAS hard disk drives per serverĪ typical Serial Attached SCSI system consists of the following basic components: The T10 technical committee of the International Committee for Information Technology Standards (INCITS) develops and maintains the SAS protocol the SCSI Trade Association (SCSITA) promotes the technology. ![]() The reverse, connecting SAS drives to SATA backplanes, is not possible. This allows the connection of SATA drives to most SAS backplanes or controllers. SAS offers optional compatibility with Serial ATA (SATA), versions 2 and later. SAS, like its predecessor, uses the standard SCSI command set. SAS replaces the older Parallel SCSI (Parallel Small Computer System Interface, usually pronounced "scuzzy" or "sexy" ) bus technology that first appeared in the mid-1980s. In computing, Serial Attached SCSI ( SAS) is a point-to-point serial protocol that moves data to and from computer-storage devices such as hard disk drives and tape drives. No submissions about memes, jokes, meta, or hypothetical / dream builds. ![]() No titles that are all-caps, clickbait, PSAs, pro-tips or contain emoji.No submissions about retailer or customer service experiences. ![]()
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