SAS Expansion Enclosure Configuration
The SAS expansion port connects to expansion enclosures. For dual-controller
systems, each expansion port connects a controller to a corresponding expansion
controller making fault-tolerant links to different SAS domains.
The following principles apply to storage system and expansion enclosure
connections:
Dual-controller storage system connects to dual-controller expansion
enclosures.
Single-controller storage system connects to single-controller expansion
enclosures.
A longer cable is available for making expansion links with a dual-controller
configuration. A longer cable is required if connections to expansion
enclosure s are made from two opposite directions. Routing through two
different connections can avoid loss of data links if one enclosure fails in
between.
There is a rotary ID switch on every expansion enclosure
that is manually configured using a flat blade screwdriver.
Configuring enclosure IDs:
The configurable IDs for expansion enclosures are from 1 to 15. Usually the
numbering starts from the one closest to the managing storage enclosure.
Make sure a unique ID is configured on each expansion enclosure so that
the SAS WWN addresses of disk drives can be properly assigned. The
storage system firmware automatically manages these addresses.
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