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Installation
SAS Expansion
As you face the rear panel of the 4U106 enclosure, the left IOM slot is 1 and the right IOM slot is 0. See also
for FRU slot index numbering for the enclosure rear panel. Green is used to show IOM 0 paths and blue is used
to show IOM 1 paths for cabling the expansion enclosures shown in each cascade.
Figure 60 Cabling the 4U106 enclosures to the storage system (1 of 2)
The diagram on the left shows the daisy chain cabling method and the diagram on the right shows the star cabling
method.
An advantage of the star configuration is that each expansion enclosure is only one additional expander or “hop” away
from the initiator. This reduces delays in the SAS communication path. Those effects are small by measure. However,
there are a limited number of expansion ports, so for larger topologies, some combination of the two approaches will be
required.
provides another daisy chain cabling example with all 12Gb/s SAS ports connected.
Daisy chain cabling method
Star cabling method
To HBA
To HBA
4U106 enclosure
4U106 enclosure
4U106 enclosure
4U106 enclosure
4U106 enclosure
4U106 enclosure
4U106 enclosure
4U106 enclosure