•
To prevent degraded performance, do not twist, fold, pinch, or step on the cables.
Cables have a minimum bend radius. Cable manufacturer specifications define the minimum
bend radius; however, a general guideline for minimum bend radius is 10 times the cable
diameter.
•
Using Velcro wraps instead of tie-wraps to bundle and secure system cables allows for easier
cable adjustments.
•
The SAS cables can be SAS copper, SAS optical, or a mix.
If you are using a mix of SAS copper cables and SAS optical cables, the following rules apply:
◦
Shelf-to-shelf connections in a stack must be all SAS copper cables or all SAS optical
cables.
◦
If the shelf-to-shelf connections are SAS optical cables, the controller-to-stack connections
to that stack must also be SAS optical cables.
◦
If the shelf-to-shelf connections are SAS copper cables, the controller-to-stack connections
to that stack can be SAS optical cables or SAS copper cables.
•
SAS optical multimode QSFP-to-QSFP cables can be used for controller-to-stack and shelf-to-
shelf connections, and are available in lengths up to 50 meters.
•
If you are using SAS optical multimode MPO cables with MPO QSFP modules, the following
rules apply:
◦
You can use these cables for controller-to-stack and shelf-to-shelf connections.
◦
The length of a single cable cannot exceed 150 meters for OM4 and 100 meters for OM3.
◦
The total end-to-end path (sum of point-to-point paths from the controller to the last shelf)
cannot exceed 510 meters.
The total path includes the set of breakout cables, patch panels, and inter-panel cables.
•
If you are using SAS optical multimode breakout cables, the following rules apply:
◦
You can use these cables for controller-to-stack and shelf-to-shelf connections.
If you use multimode breakout cables for a shelf-to-shelf connection, you can only use it
once within a stack of disk shelves. You must use SAS optical multimode QSFP-to-QSFP
or MPO cables with MPO QSFP modules to connect the remaining shelf-to-shelf
connections.
◦
The point-to-point (QSFP-to-QSFP) path of any multimode cable cannot exceed 150
meters for OM4 and 100 meters for OM3.
The path includes the set of breakout cables, patch panels, and inter-panel cables.
◦
The total end-to-end path (sum of point-to-point paths from the controller to the last shelf)
cannot exceed 510 meters.
The total path includes the set of breakout cables, patch panels, and inter-panel cables.
◦
Up to one pair of patch panels can be used in a path.
◦
You need to supply the patch panels and inter-panel cables.
The inter-panel cables must be the same mode as the SAS optical breakout cable:
multimode.
◦
You received a set of QSFP-to-MPO cable modules with each set of SAS optical breakout
cables, which you must attach to the MPO end of each SAS optical breakout cable.
The breakout cables have SC, LC, or MTRJ connectors on the opposite end, which connect
to a patch panel.
◦
You must connect all eight (four pairs) of the SC, LC, or MTRJ breakout connectors to the
patch panel.
•
You cannot change any disks, disk shelves, or components of a controller module as part of
these procedures.
DS4243, DS2246, DS4486, and DS4246 Installation and Service Guide
48
Replacing disk shelf components
