Drive bay numbering: SAS expander

Drive numbering through a SAS Expander is continuous.

  • SAS expander port 1 always connects to port 1 of the controller.
  • SAS expander port 2 always connects to port 2 of the controller.
  • SAS expander port 3 = drive numbers 1-4.
  • SAS expander port 4 = drive numbers 5-8.
  • SAS expander port 5 = drive numbers 9-12.
  • SAS expander port 6 = drive numbers 13-16.
  • SAS expander port 7 = drive numbers 17-20.
  • SAS expander port 8 = drive numbers 21-24.
  • SAS expander port 9 = drive numbers 25-28.

Common configuration examples:




4 LFF device bay numbering

When any stacked 2SFF drive configuration is connected to the SAS expander, the drive numbering skips the second number to allow uFF drive bay numbering.

  • Front 2SFF to SAS expander port 3:



  • Rear 2SFF to SAS expander port 9:



  • Front 2SFF side-by-side (unstacked) to SAS expander port 3:

  • Rear 3LFF to SAS expander port 9:

  • Mid 4LFF to SAS expander port 6:


  • Front 12LFF + Midplane 4LFF + All rear 2SFF: