Cisco Nexus 7000 Hardware Installation And Reference Manual page 211

Appendix 8 Managing the Switch Hardware
Table 8-2 Power Supply Redundancy Mode Scenarios
Power Power
Supply 1 Supply 2
Scenario (kW) (kW)
1 3.0 6.0
2 3.0 6.0
3 3.0 6.0
OL-23069-06
The following three scenarios explain what happens depending on what you install for the third
power supply unit:
Scenario 1: If you do not add a third power supply unit, the reserve power is 6 kW and the
available power is 3 kW. The available power is insufficient for the switch power requirement,
so you cannot power the entire switch.
Scenario 2: If you add a power supply unit that outputs 3 kW, the reserve power remains 6 kW
and available power becomes 6 kW. The available power is still insufficient because it does not
meet the switch power requirement, so you can power more modules than you could with
Scenario 1, but you still cannot power the entire switch.
Scenario 3: If you add a power supply unit that outputs 7.5 kW, the reserve power becomes
7.5 kW and the available power becomes 9 kW. The available power exceeds the switch power
requirement, so you can power up all of the modules and fan trays in the switch.
Table 8-2 shows the results for each scenario.
Power System Available
Supply 3 Usage Power
(kW) (kW) (kW)
— 8.784 6.0
3.0 8.784 6.0
7.5 8.784 9.0
Input source redundancy mode—To activate this power mode, use the
–
power redundancy-mode insrc_redundant command. The reserve power is the greater of
power outputs for the two grids, and the available power becomes the lesser of power outputs
for the two grids.
For example, suppose your system has the following setup:
Grids 1 and 2 each input 220 V to the power supply units.
Power supply units 1 and 2 each output 6 kW.
Current usage requirement is 8.784 kW.
The following three scenarios explain what happens for different numbers of power supply units
that you install:
Scenario 1: If you do not add a power supply unit, the reserve power is 6 kW (3 kW for one
power supply unit and 3 kW for the other power supply unit), and the available power is 6 kW
(3 kW for one power supply unit plus 3 kW for the other power supply unit). The available
power does not meet the switch usage requirement, so you cannot power the entire switch.
Reserve
Power
(kW) Result
— The available power does not meet the system
usage requirement, so you cannot power the entire
system with this power supply configuration and
mode.
6.0 The available power does not meet the system
usage, so you cannot power the entire system with
this power supply configuration and mode.
7.5 The available power exceeds the system usage, so
you can power the entire system with this power
supply configuration and mode.
Cisco Nexus 7000 Series Hardware Installation and Reference Guide
Power Supply Configuration Modes
8-13