User's Manual

Power Management 259
No Redundancy
Power from up to three PSUs is used to power the entire chassis. So in
a 6-PSU chassis, a chassis continues to operate at full capacity if
any 3 PSUs fail.
CAUTION: The No Redundancy mode uses only three PSUs without a backup.
Failure of one of the three PSUs being used could cause servers to lose power
and data.
Power Conservation and Power Budget Changes
The CMC performs power conservation when the user-configured maximum
power limit is reached. When the demand for power exceeds the user
configured System Input Power Cap, the CMC reduces power to servers in
reverse-priority order to free power for higher priority servers and other
modules in the chassis.
If all or multiple slots in the chassis are configured with the same priority
level, the CMC decreases power to servers in increasing slot number order.
For example, if the servers in slots 1 and 2 have the same priority level, the
power for the server in slot 1 is decreased before that of the server in slot 2.
NOTE: You can assign a priority level to each of the servers in the chassis by giving
each server a number from 1 through 9. The default priority level for all servers is 1.
The lower the number, the higher the priority level.
For instructions on assigning server priority levels, see "Using RACADM."
You can assign server priority using the GUI:
1
Click Servers in the system tree .
2 Select the Power Management tab → Priority sub-tab.
PSU Failure With Degraded or No Redundancy Policy
The CMC decreases power to servers when an insufficient power event
occurs, such as a PSU failure. After decreasing power on servers, the CMC
re-evaluates the power needs of the chassis. If power requirements are still not
met, CMC may also power off the lower priority blade servers.
Power for higher priority servers is restored incrementally while power needs
remain within the power budget.
NOTE: To set the redundancy policy, see "Configuring Power Budget and
Redundancy."