Installation Considerations - Power Supply Modules Of Different Capacities - Cisco Catalyst 9404R Switch Hardware Installation Manual

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Installation Considerations - Power Supply Modules of Different Capacities

N+1 Redundant Mode
N is the number of active power supply modules and can be one to seven power supply modules. +1 is the
power supply module reserved for redundancy and must be configured as the standby module (power
redundancy-mode command).
The default standby power supply slot on a seven-slot or a ten-slot chassis is 8. The default standby power
supply slot on a four-slot chassis is 4. To designate a different slot as standby, enter the power
redundancy-mode command.
N+N Redundant Mode
N number of power supplies are active, and n number of power supply modules are configured as standby
(power redundancy-mode command).
For detailed software configuration information, see the System Management → Environmental Monitoring
and Power Management section of the software configuration guide for the required release.
Installation Considerations - Power Supply Modules of Different Capacities
You can install power supplies of different capacities in a Cisco Catalyst 9400 Series chassis.
If you do, and you use the default power supply mode, which the combined mode, there are no additional
factors to consider. However, in the redundant mode (n+1 and n+n), you must observe the guidelines outlined
here.
Note
While the installation of power supplies of different capacities in the same chassis is supported, it is not an
optimal use of total system power in a redundant mode.
N+1 Redundant Mode with Power Supplies of Different Capacities
The power supply module with the highest wattage or capacity must be configured as the standby.
N+N Redundant Mode with Power Supplies of Different Capacities
At the time of switch over to standby power, the total standby output power must be greater than or equal to
the total active output power at the time of a switch over (total standby output power >= total active output
power).
Cisco Catalyst 9400 Series Switches Hardware Installation Guide
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