Backplanes are the fundamental building block to any storage appliance that is meant to support hot plugging. So, SAS expanders will always go hand in hand with powerful backplanes (whether these are in a single box or not). Usually, one link is used to attach a simple backplane to the host adapter or to a hop. Expanders with built-in backplanes will of course use multi-link connects.
Three connector types are allowed for SAS: SFF-8484 is a multi-lane internal cable that links a host adapter to a backplane. This can also be achieved by splitting the cables into multiple single SAS connectors on one end (see image below). SFF-8482 is the connector that links a drive to a single SAS port. Finally, SFF-8470 is the external multi-link cabling solution. It has a maximum cable length of six meters.
Source: Adaptec.
This is a SFF-8470 cable for external multi-lane SAS links.
This is a SFF-8484 multi-lane cable. It runs four links via one connector.
Here we have a SFF-8484 cable that is used to attach four SATA drives.
Stay On the Cutting Edge: Get the Tom's Hardware Newsletter
Get Tom's Hardware's best news and in-depth reviews, straight to your inbox.
Patrick Schmid was the editor-in-chief for Tom's Hardware from 2005 to 2006. He wrote numerous articles on a wide range of hardware topics, including storage, CPUs, and system builds.
