Power-supply (n+1) redundancy mode
This mode allocates one power supply as a reserve power supply in case an available power supply
fails. The remaining power supplies are allocated for available power. The reserve power supply must
be at least as powerful as each power supply used for the available power.
For example, if a switch requires 7.1 kW of available power and the switch has four power supplies
that each output 3-kW, then three of the power supplies provide 9.0 kW of available power and one
power supply provides 3.0 kW of reserve power in case another power supply fails.
Input-source (grid) redundancy mode
This mode allocates half of the power to available power and the other half to reserve power. You must
use a different power source for the active and reserve power sources so that if the power source used
for active power fails, the other power source used for the reserve power can provide power for the
switch.
For example, if the switch requires 7.1 kW of power, the switch has six power supplies that each output
3 kW, and there are two 220-V power grids, then you use grid A to power three 3-kW power supplies
that provide the available power to power the switch and you use grid B to power the other three 3-kW
power supplies that provide the reserve power in case grid A fails.
Full redundancy mode
This mode provides both power-supply (
n
+1) and input-source (grid) redundancies. As happens with
the input-source redundancy mode, this mode allocates half of the power supplies to provide available
power and the other half of the power supplies to provide the reserve power. One of the reserve power
supplies can alternatively be used to provide power if a power supply supplying the available power
fails.
Guidelines for Configuring Power Redundancy Modes
The amounts of available and reserve power depend on the power redundancy mode that you specify and the
number of power supplies installed in the switch. For each redundancy mode, consider the following:
Cisco Nexus 7718 Switch Site Preparation and Hardware Installation Guide
84
OL-30453-01
Managing the Switch
Guidelines for Configuring Power Redundancy Modes