Dell Chassis Management Controller Version 6.20 for PowerEdge M1000e User’s Guide

New Server Engagement Policy

If a new server that is turned on exceeds the power available for the chassis, CMC may decrease the power to the low-priority servers. This allows more power for the new server. This happens if:

The administrator had configured a power limit for the chassis that is below the power required for full power allocation to the servers.
Insufficient power is available for the worst-case power requirement of all servers in the chassis.

If enough power cannot be freed by reducing the power allocated to the lower priority servers, the new server may not be allowed to turn on.

The highest amount of sustained power required to run the chassis and all the servers, including the new one, at full power is the worst-case power requirement. If that amount of power is available, then no servers are allocated power that is less than the worst-case power needed and the new server is also allowed to turn on.

The following table provides the actions taken by CMC when a new server is turned on in the scenario described earlier.

Table 1. CMC Response When a Server Power-On is Attempted . The following table describes the CMC responses when a server power-on is attempted.
Worst Case Power is Available	CMC Response	Server Power On
Yes	No power conservation is required	Allowed
No	Perform power conservation: Power required for new server is available Power required for new server is not available	Allowed Disallowed

If a PSU fails, it results in a non-critical health state and a PSU failure event is generated. The removal of a PSU results in a PSU removal event.

If either event results in a loss of redundancy, based on power allocations, a loss of redundancy event is generated.

If the subsequent power capacity or the user power capacity is greater than the server allocations, servers have degraded performance or, in a worse case, servers may be powered down. Both conditions are in reverse-priority order, that is, the lower priority servers are powered down first.

The following table provides the firmware response to a PSU power down or removal as it applies to various PSU redundancy configurations.

Table 2. Chassis Impact from PSU Failure or Removal . The following table describes the impact of PSU failure or removal on the chassis.
PSU Configuration	Dynamic PSU Engagement	Firmware Response
Grid Redundancy	Disabled	CMC alerts you of loss of Grid Redundancy.
Power Supply Redundancy	Disabled	CMC alerts you of loss of Power Supply Redundancy.
No Redundancy	Disabled	Decrease power to low priority servers, if needed.
Grid Redundancy	Enabled	CMC alerts you of loss of Grid Redundancy. PSUs in standby mode (if any) are turned on to compensate for power budget lost from the PSU failure or removal.
Power Supply Redundancy	Enabled	CMC alerts you of loss of Power Supply Redundancy. PSUs in standby mode (if any) are turned on to compensate for power budget lost from PSU failure or removal.
No Redundancy	Enabled	Decrease power to low priority servers, if needed.