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The storage processors connect to the DAEs with mini-SAS HD cables. The cables connect LCCs in the DAEs of a storage
platform in a daisy-chain topology. The mini-SAS HD ports on the storage processors in the DPE are labeled 0 and 1. Mini-SAS
HD port 0 is connected internally to the SAS expander that connects the drives on the front of the DPE.
Each DAE supports two redundant connections to the DPE: LCC A and LCC B.
It is recommended that you connect the first optional DAE to the mini-SAS HD output port 1 of each storage processor. This
connection creates back-end bus 1 (BE1) and designates this DAE as enclosure 0 of this bus. The address of this enclosure is
BE1 Enclosure 0. In a two back-end bus system, it is recommended that you connect the second optional DAE to the mini-SAS
HD port 0 of each storage processor.
DAE load balancing
If your system has several optional DAEs, you can daisy-chain them within that bus. However, it is recommended that you
balance each bus. In other words, optimize your environment by using every available bus, and spread the number of enclosures
and drives as evenly as possible across the buses. The rule of load or bus balancing is applied to all DAEs.
Cabling the first optional DAE to create back-end bus
1
Connect the first optional expansion DAE to port 1 of the DPE to create back-end bus 1 (BE1) and designate this DAE as
enclosure 0 of this bus. We refer to the address of this enclosure as BE1 Enclosure 0 (1_0).
About this task
To prepare for this cabling task:
● Locate the mini-SAS HD cables to be used to connect to the newly installed expansion DAE. Typically these cables are
two-meters long. You use longer cables, typically five-meters or eight-meters, to connect enclosures located in different
racks. Cables are shipped without labels attached. The cables and ports are not colored.
● Locate the sheet of cable labels provided.
Orient the cable connectors as described in the procedure that follows, making sure that you do NOT connect:
● A DPE expansion port 0 to another DPE expansion port 0
● Any A-side ports to B-side ports
Steps
1. Label a pair of mini-SAS HD cables.
2. Connect port 1 on SP A in the bottom slot of the DPE to port A on the link control card (LCC A) in the bottom of the DAE.
3. Connect port 1 on SP B in the top slot of the DPE to port A on the link control card (LCC B) in the top of the DAE.
Example
Figure 22. Cabling one DPE to one 25-drive DAE
A B
B A
0 1
1 0
Installation Procedures
29
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