SAS allows a higher transfer speed (3, 6 or 12Gbit/s) than most parallel SCSI standards. SAS achieves these speeds on each initiator-target connection, hence getting higher throughput, whereas parallel SCSI shares the speed across the entire multidrop bus. SAS-1.1 topologies built with expanders generally contain one root node in a SAS domain with the one exception case being topologies that contain two expanders connected via a subtractive-to-subtractive port. If it exists, the root node is the expander, which is not connected to another expander via a subtractive port. Therefore, if a fanout expander exists in the configuration, it must be the domain's root node. The root node contains routes for all end devices connected to the domain. Note that with the advent in SAS-2.0 of table-to-table routing and new rules for end-to-end zoning, more complex topologies built upon SAS-2.0 rules do not contain a single root node. Also I would like to run it with Raid 50 and IPMI ports are important since I remote in a lot and want to be able to remotely reboot and manage that too... etc, etc. The SFF-8643 is the latest HD MiniSAS connector design for implementing HD SAS Internal interconnect solutions.

These newer SFF-8643 and SFF-8644 HD SAS connector interfaces have essentially replaced the older SFF-8088 external and the SFF-8087 internal SAS interfaces, however CS Electronics continues to support our customers’ needs for the older interface cables and adapters. Mini Multilane 4/8X 12 Gb/s Shielded Cage/Connector (HD12sh), Rev 3.5". Archived from the original on November 12, 2020. In addition, every SAS device has a SCSI device name, which identifies the SAS device uniquely in the world. One doesn't often see these device names because the port identifiers tend to identify the device sufficiently. 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. 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.a b "24G SAS Data Storage Specification Development Complete; SCSI Trade Association Spotlights Technology at 2017 Flash Memory Summit". SCSI Trade Association. 2017-08-07. SAS is full duplex, whereas SATA is half duplex. The SAS transport layer can transmit data at the full speed of the link in both directions at once, so a SCSI command executing over the link can transfer data to and from the device simultaneously. However, because SCSI commands that can do that are rare, and a SAS link must be dedicated to an individual command at a time, this is generally not an advantage with a single device. [12] Serial Attachment 2X 12 Gb/s Unshielded Connector, Rev 2.1". Archived from the original on June 6, 2021. Shielded High Speed Serial Multilane Copper Connector, Rev 3.3". Archived from the original on June 6, 2021.

Mini Multilane 4X Shielded Connector Shell and Plug, Rev 3.4". Archived from the original on November 14, 2020. SAS error-recovery and error-reporting uses SCSI commands, which have more functionality than the ATA SMART commands used by SATA drives. [11] Serial Attached SCSI - 4 (SAS-4), 5.8.1 General electrical characteristics" (PDF) . Retrieved 2015-05-11. No need for using Serial ATA Tunneling Protocol (STP), which is necessary for SATA HDDs to be connected to a SAS HBA. [56] :16Direct routing allows a device to identify devices directly connected to it. Table routing identifies devices connected to the expanders connected to a device's own PHY. Subtractive routing is used when you are not able to find the devices in the sub-branch you belong to. This passes the request to a different branch altogether. 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. A target device could be a hard disk drive or a disk array system. Expanders with no PHYs configured as subtractive act as fanout expanders and can connect to any number of other expanders. Expanders with subtractive PHYs may only connect to two other expanders at a maximum, and in that case they must connect to one expander via a subtractive port and the other via a non-subtractive port. SAS protocol provides for multiple initiators in a SAS domain, while SATA has no analogous provision. [11] SAS Device to Mid-plane Interconnects Roadmap". SCSITA.org. SCSI Trade Association. 2015-08-15 . Retrieved 2017-10-14.

Multilane Unshielded Serial Attachment Connectors, Rev 2.0". Archived from the original on June 6, 2021.

SFF-8643

I know that standard SFF-8087 only supports 4 lanes on a single connector. SFF-8643 supports 4 or 8 according to everything i've read, including Wikipedia reference ( https://en.wikipedia.org/wiki/Serial_Attached_SCSI) 0n a single connector. Serial Attachment 2X 24 Gb/s Unshielded Connector, Rev 1.0". Archived from the original on June 6, 2021.

SAS 4.0, PCI-E 4.0, Upcoming 24Gbps, New HBA's and RAID cards, SlimSAS, My New "Cables" and the new SFF Connector: The Future Is Here, Bois". ServeTheHome Forums. 30 March 2021. Archived from the original on May 27, 2021 . Retrieved 2021-07-10.Mini Multilane 4X Unshielded Connector Shell and Plug, Rev 2.6". Archived from the original on January 29, 2019. For comparison, in parallel SCSI, the SCSI ID is the port identifier and device name. In Fibre Channel, the port identifier is a WWPN and the device name is a WWNN. Unshielded I/O Connector, Rev 1.2". Archived from the original on July 10, 2021 . Retrieved July 10, 2021. Most SAS drives provide tagged command queuing, while most newer SATA drives provide native command queuing. [11] Additionally, SCSI Express takes advantage of the PCI Express infrastructure to directly connect SCSI devices over a more universal interface. [15] Architecture [ edit ] The architecture of SAS layers