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
Cables
on page 31.)
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 Controller
on page 41, the 4-wide internal SAS connector forms links with four independent disk
drives.)
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
Cables
on
page 31.
How are Disk Drives Identified in SAS?
In the BIOS and in the management utilities (see
Identifying Disk Drives
on page 90), disk drives are
identified in the following formats:
• CNX:DevY = Device Y is attached to Connector X (see
Direct-attach Connections
on page 71 for more
information)
• BoxX:SlotX = Enclosure X is attached to a disk drive in Slot X (see
Backplane Connections
on page
72 for more information)
• ExpX:PhyX = Expander X is attached to Phy X (see
SAS Expander Connections
on page 72 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).
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 Connections
on page 72),
you can create large configurations.
Direct-attach Connections
In a direct-attach connection, SAS or SATA disk drives are connected directly to a SAS card with SAS or
mini-SAS cables. One disk drive is attached to one SAS/mini-SAS connector with one SAS/mini-SAS cable
(or multiple disk drives are attached to one SAS/mini-SAS connector with one fan-out cable). The figure
in
Connecting Drives Directly to the Controller
on page 41 shows an example of direct-attach connections.
71
Proprietary and Confidential to PMC-Sierra, Inc.
Document No.: CDP-00277-02-A Rev. A, Issue:
Serial Attached SCSI RAID Controllers Installation and User's Guide