Power Redundancy

In simple terms, power redundancy (N+1) protects the system from shutting down.

With redundancy, if the output of one PSU is lost for any reason, the system remains fully powered. In this scenario, N is the minimum number of power supplies needed to keep the system fully powered and the system has N+1 PSUs powered.

If the system power status is not redundant, the removal of one PSU, the loss of power to one PSU, or a degradation of input voltage results in insufficient power to keep all of the I/O and Fabric (BlackDiamond X8 series only) modules powered up. If there is not enough power, ExtremeXOS powers down the modules as follows:

If you install or provide power to a new PSU, modules powered down due to earlier insufficient power are considered for power up from the lowest slot number to the highest slot number, based on the module‘s power requirements (see I/O and Fabric Module Power Priority).

Whenever the system experiences a change in power redundancy, including a change in the total available power, degraded input voltage, or a return to redundant power, the switch sends messages to the syslog.