EMC VNX Series Hardware Information Manual page 87

Cabling with two DAEs in VNX5300 Block platform
IMPORTANT
Do Not
connect more DAEs than the VNX5300 platform can support. When calculating the
number of drives for your VNX5300 platform, the DPE is included in the total drive slot
quantity of 120 to 125 drives. If the total drive slot quantity exceeds 120 or 125, you will
not be able to add another DAE.
The first DAE connected to the Storage Processor SAS 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 SAS Port 0 will be on ID 0, but the addresses
will increment.
Figure 77 on page 88 shows the first example of a VNX5300 Block platform with two DAEs
(one 3U, 15 disk drive DAE and the other a 2U, 25 disk drive DAE) or a VNX5300 platform
with a total of from 55 disk drives (if the DPE is a 3U, 15 disk drive device) or 65 disk
drives (if the DPE is a 3U, 25 disk drive device).
The SAS ports on the VNX5300 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 77 on page 88, 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 VNX5300 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 VNX5300 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.
Note: On the DPE and DAE, each cable connector includes a symbol to denote the
direction the cable needs to connect to. The cable connector that has a double circle
symbol is the input to the device. The cable connector with the double diamond
symbol is the output from the device.
IMPORTANT
Notice the description of the cable labels affixed to the SP to DAE cables.
EMC VNX5300 Hardware Information Guide
VNX5300 DAE cabling
87