Unlike SCSI devices and SCSI IDs, SAS devices self-configure their SAS addresses. User intervention is not
required to set SAS addresses, and SAS addresses cannot be modified.
A.7
What’s a SAS Connector?
A SAS or mini-SAS connector is the physical plug or receptacle that you see on a SAS device. It's what you
plug a SAS cable into, or the end of the SAS cable that’s being plugged in. (See
Cablescontrollers SAS cablesSAS
.)
A connector is what forms physical links between phys. Some SAS connectors can support multiple links.
The number of links a SAS connector can support is referred to as its width. Narrow connectors support a
single link; wide connectors supports more than 1 link.
A single SAS device may have one or more connectors. A single SAS connector may help form links between
more than two SAS devices. (For instance, as shown in the figure in
Connecting Drives Directly to the
Controllerinstallation direct-attachdirect-attach connections
, the 4-wide internal SAS connector forms links
with four independent disk drives.)
A.8
What do SAS Cables Look Like?
Internal standard SAS cables are narrower than internal parallel SCSI cables. The connectors vary in size
depending on the number of links they support, from single link connectors to 4-wide (or larger) connectors.
Internal fan-out cables let you attach four disk drives to a single 4-wide connector.
Mini-SAS connectors support both internal and external SAS connections. The mini-SAS connectors are
smaller than the standard SAS internal and external connectors. Mini-SAS connectors support single and
multilinks with the ability to scale to future speed needs.
For examples of some internal SAS/mini-SAS cables and an external SAS/mini-SAS cables, see
.
A.9
How are Disk Drives Identified in SAS?
In the BIOS and in the management utilities (see
Identifying Disk Drives disk drives identifying
), disk drives
are identified in the following formats:
• CNX:DevY = Device Y is attached to Connector X (see
Direct-attach ConnectionsSAS direct-attach
connectionsdirect-attach connections
for more information)
• BoxX:SlotX = Enclosure X is attached to a disk drive in Slot X (see
Backplane ConnectionsSAS backplane
connectionsbackplane connections
for more information)
• ExpX:PhyX = Expander X is attached to Phy X (see
SAS Expander ConnectionsSAS expander
connectionsexpander connections
for more information)
where X is the count number.
Note: Devices other than disk drives (CDROM, tape drives, etc...) are listed in order after
your system disk drives.
In parallel SCSI, XX is the disk drive’s channel number, YY is the target number, and ZZ is the logical unit
number (LUN).
A.10
What are the SAS Connection Options?
You can connect end devices to each other through direct cable connections and through backplane
connections. When you use one or more expander devices (see
SAS Expander ConnectionsSAS expander
connectionsexpander connections
), you can create large configurations.
46
Microsemi Proprietary and Confidential. Installation and User's Guide Revision 5
Introduction to SAS
