Cisco Nexus 9508 - Page 80

Combined mode
The available power equals the combined output of all installed power supplies. There is no reserve
power. You activate this mode by using the power redundancy-mode combined command.
For example, if the power requirement for a switch is 5.2 kW and the switch has one 3-kW power
supply with 220-V input and 3.0-kW output, consider the following power planning scenarios:
• Scenario 1—No added power supplies
If you do not add a power supply unit, the available power (3.0 kW) is insufficient for the switch
power requirement of 5.2 kW, so the switch powers the supervisor modules, system controllers,
fan trays, and at least one fabric module before powering as many of the fabric and line cards as
the remaining available power can support (one or more fabric or line cards might not be powered).
• Scenario 2—Install an extra 3-kW power supply
If you install an additional 3-kW power supply unit that can output 3.0 kW, the available power
becomes 6.0 kW. The increased amount of available power exceeds the switch power requirement
of 5.2 kW, so all of the modules and fan trays in the switch can power up.
The following table shows the results for each scenario.
ResultReserve
Power
Available
Power
Power
Supply 2
Output
Power
Supply 1
Output
Power
Requirement
Scenario
Available power is less
than the power
requirement for the
switch, so you cannot
power the entire switch
(some of the line cards
will not be able to power
up).
—
3.0 kW
—
3.0 kW5.2 kW1
Available power exceeds
the power requirement
for the switch, so the
entire switch can power
up.
—
6.0 kW3.0 kW3.0 kW5.2 kW2
Cisco Nexus 9508 NX-OS Mode Switch Hardware Installation Guide
70
Managing the Switch
Power Mode Configuration Guidelines