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:

BlackDiamond X8: I/O modules from the highest numbered slot to lowest numbered slot are powered down, and then Fabric modules from the highest numbered slot to lowest numbered slot are powered down until the switch has enough power to continue operation (see I/O and Fabric Module Power Priority).
BlackDiamond 8800 series: I/O modules from the highest numbered slot to lowest numbered slot are powered down until the switch has enough power to continue operation (see I/O and Fabric Module Power Priority).

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.

Published March 2020prev | next

Email this topic

Print this page Print this page

Leave feedback Feedback