IBM N Series, Hardware Manual

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IBM System Storage N series Hardware Guide
򐂰 If you are using SAS optical multimode breakout cables, the following parameters apply:
– You can use these cables for controller-to-shelf and shelf-to-shelf connections.
– If you use multimode breakout cables for a shelf-to-shelf connection, you can use it
only 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 must supply the patch panels and inter-panel cables. The inter-panel cables must
be the same mode (multimode) as the SAS optical breakout cable.
– You must attach the set of QSFP-to-MPO cable modules that you received with each
set of SAS optical breakout cables 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.
򐂰 If you are using SAS optical singlemode breakout cables, the following parameters apply:
– You can use these cables for controller-to-shelf connections. Shelf-to-shelf connections
use multimode QSFP-to-QSFP cables or multimode MPO cables with MPO QSFP
modules.
– The point-to-point (QSFP-to-QSFP) path of a single singlemode cable cannot exceed
500 meters.
– 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 must supply the patch panels and inter-panel cables. The inter-panel cables must
be the same mode as the SAS optical breakout cable: singlemode.
– You must connect all eight (four pairs) of the SC, LC, or MTRJ breakout connectors to
the patch panel.
򐂰
The SAS cables can be SAS copper, SAS optical, or a mix depending on whether your
system meets the requirements for using the type of cable. 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 shelf-to-controller
connections to that stack must also be SAS optical cables.
– If the shelf-to-shelf connections are SAS copper cables, the shelf-to-controller
connections to that stack can be SAS optical cables or SAS copper cables.