nomen est omen#

basics#

todo: sas topology

• connector: physical connection where to plug in cables
• controller: generic term for both hbas and raid adapters
• hba: host bus adapter, sas controller to allow direct access to disks
• sas:
• sff-8482: most common connector to direct connect sas disks
• port: collection of phy’s
• phy: part of sas assembly that creates the physical link

the whole shebang#

todo - lots to add

• sas speeds

  • sas-1: 3gb/s
  • sas-2: 6gb/s
  • sas-3: 12gb/s
  • sas-4: 22.5gb/s
    • marketed as 24gb/s

• tri mode card: card that does sata, sas and nvme

• sas address

• controller

• hba

• jbod

• raid

• nearline sas

• narrow port: port that is connected using only 1 phy

• wide port

• dual port:

• standards (incits)

  • sam: scsi architecture model
  • sbc: scsi block commands
  • spc: scsi primary commands
  • spl: sas protocol layer
  • zbc: zoned block commands

• sas expander

  • sas-2 and later have a simple rule
    • if the expander connects only to the hba & other expanders it may connect as many expanders as it’s connectors allow
    • if there are 1 or more end devices attached it may connect at most to 2 other expanders, or 1 expander and 1 hba
  • sas-1 defined 2 types of expanders
    • sas edge expander (connects 128 devices)
    • sas fanout expander (connects 128 edge expanders)

• sas domain max 16384 sas ports / addresses

• connector: physical connector to plug in cables

  • connector assembly
  • connector mechanical

• phy

• lane: only used in pcie context; not sas context

• vpd: vital product data

• stp: serial ata tunneled protocol

• smp: sas serial management protocol

• ses: scsi enclosure services

• ssp: serial scsi protocol