132 EMC VNX5400 Hardware Information Guide
VNX5400 DAE cabling
Cabling with two DAEs in a VNX5400 File/Unified platform
Shown in the upcoming figure (Figure 109 on page 133) is a graphical representation of
SAS cabling in a DPE-based VNX storage platform, the VNX5400 File. The Storage
Processors connect to the DAEs with SAS cables. The cables connect LCCs in the DAEs of a
storage platform in a daisy-chain topology.
The DPE is automatically Enclosure 0 (EA 0). The DAE connected to mini-SAS HD output
port 0 is Enclosure 1 (EA1).
The first DAE connected to the Storage Processor mini-SAS HD output port 1 is designated
Enclosure 0 (EA0). Each DAE connected after the first DAE increments the enclosure
number by one. All enclosures connected to mini-SAS HD Port 0 will show an ID of 0.
Figure 109 on page 133 shows the first example of a VNX5400 File platform with two DAEs
(one 3U, 15 disk drive DAE and the other a 2U, 25 disk drive DAE) or a VNX5400 platform
with a total of from 65 disk drives (the DPE is a 3U, 25 disk drive device).
The mini-SAS HD ports on the VNX5400 platform 3U DPE are labeled 0 and 1. SAS 0 is
connected internally to the SAS expander that connects the internal DPE disks. Since SAS
0 is already connected internally to the DPE disks, the first DAE is connected to SAS 1 to
balance the load on the SAS ports. The second DAE is connected to SAS 0, the third DAE is
connected to SAS 1, and so on.
In Figure 109 on page 133, notice that each DAE device supports two completely
redundant buses (LCC A and LCC B).
The rule of load or bus balancing is applied to all DAEs. That is, Bus 0 is Enclosure
Address 0 (EA0), Bus 1 is EA0, and so on. In the case of the VNX5400 platform, Bus 0 EA0
is the DPE (SP A and B). So, to balance the load, Bus 1 EA0 becomes the first DAE (LCC A
and B) in the cabinet with the next DAE (LCC A and LCC B) as Bus 0 EA1, and so on. If you
have several DAEs in your VNX5400 platform, you can daisy chain them within that
particular bus. However, it is recommended that you balance each bus. In other words,
always optimize your environment by using every available bus, and spreading the
number of enclosures as evenly as possible across the buses.
Notice the description of the cable labels affixed to the SP to DAE cables.
The cables shown in Figure 109 on page 133 are:
Note: The cable colors shown in the example are orange for Bus 0 and blue for Bus 1.
◆ Cable 1, orange, DPE to 2
nd
DAE (labels SP A SAS 0 to LCC A)
◆ Cable 2, orange, DPE to 2
nd
DAE (labels SP B SAS 0 to LCC B)
◆ Cable 3, blue, DPE to 1
st
DAE (labels SP A SAS 1 to LCC A)
◆ Cable 4, blue, DPE to 1
st
DAE (labels SP B SAS 1 to LCC B)