Full redundancy mode
Full redundancy provides both power-supply redundancy and input-source redundancy. For power-supply
redundancy, the power supply with the most output provides reserve power and the other power supplies
provide the available power. For input-source redundancy, the available power is provided by one
power source and the reserve power is provided by another power source ,with half of the 3-kW power
supplies powered by one source and the other half powered by the other source. You activate this power
mode by using the
power redundancy-mode redundant
command.
For example, if the power requirement for a switch is 2.8 kW, the switch uses two 110-V power sources,
and the switch has two 3-kW power supplies (each outputting 1.45 kW for 110-V power sources),
consider the following power planning scenarios:
•
Scenario 1
—
no added power supplies
The available power is 1.45 kW (output from one 3-kW power supply using a 110-V power source)
and the reserve power is 1.45 kW (output from the other power supply). The available power does
not meet the switch requirements of 2.8 kW, so most of the modules will power up but one or
more I/O modules will not be able to power up.
•
Scenario 2
—
adding two 3-kW power supplies
The available power is 2.9 kW (output from two 3-kW power supplies using a 110-V power
source) and the reserve power is 2.9 kW (output from the other two power supplies). The available
power (2.9 kW) exceeds the power requirement of the switch (2.8 kW), so the entire switch can
power up.
The following table shows the results for each scenario.
Result
Power
Source
Redundancy
Input Source
Redundancy
Output for Power
Supplies
Power
Rqmnt
Scenario
Res.
Avail.
Res.
Avail.
4
3
2
1
Available power for both
redundancies does not meet
the switch requirements, so
some of the I/O modules
cannot power up.
1.45
kW
1.45
kW
1.45
kW
1.45
kW
—
—
1.45
kW
1.45
kW
2.8
kW
1
Available power for both
redundancies exceeds the
switch requirements, so the
entire switch can power up.
1.45
kW
4.35
kW
2.9
kW
2.9
kW
1.45
kW
1.45
kW
1.45
kW
1.45
kW
2.8
kW
2
Configuring the Power Mode
You can configure the power supply mode by using the
power redundancy-mode
command.
Cisco Nexus 7718 Switch Site Preparation and Hardware Installation Guide
88
OL-30453-01
Managing the Switch
Configuring the Power Mode