Cisco Nexus 7000 Series Hardware Installation And Reference Manual page 178

Power Supply Configuration Modes
S e n d d o c u m e n t c o m m e n t s t o n e x u s 7 k - d o c f e e d b a c k @ c i s c o . c o m
Table 7-3
Scenario
1
2
Table 7-4 Power Supply Redundancy Mode Scenarios
Power Power
Supply 1 Supply 2
Scenario (kW) (kW)
1 3.0 6.0
Cisco Nexus 7000 Series Hardware Installation and Reference Guide
7-14
Combined Power Mode Scenarios
Power Power
Supply 1 Supply 2
(kW) (kW)
6.0 —
6.0 3.0
Power supply redundancy mode—To activate this power mode, use the
–
power redundancy-mode ps-redundant command. The power supply unit that outputs the
most power provides the reserve power, and the combined output for the other power supply
units becomes the available power.
For example, suppose your system has the following setup:
Power supply unit 1 outputs 3.0 kW.
Power supply unit 2 outputs 6.0 kW.
The switch power requirement is 8.784 kW.
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 7-4 shows the results for each scenario.
Power System Available
Supply 3 Usage Power
(kW) (kW) (kW)
— 8.784 6.0
System Available
Usage Power
(kW) (kW) Result
8.784 6.0 Available power is less than system usage, so
you cannot power the entire system with this
mode.
8.784 9.0 Available power exceeds the system usage, so
you can use this mode to power your entire
system.
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.
Chapter 7 Managing the Switch Hardware
OL-23069-06