User's Manual

Power Management 203
Figure 8-3. No Redundancy
New Server Engagement Policy
When a new server is powered on, the CMC may need to decrease power to
lower priority servers to allow more power for the new server if adding the new
server exceeds the power available for the system. This could happen if the
administrator has configured a power limit for the chassis that is below what
would be required for full power allocation to the servers, or if fewer than
three power supplies are in the chassis. If enough power cannot be freed by
throttling lower priority servers the new server may not be allowed to start.
The highest sustained power required to run the chassis and all of the servers,
including the new one, at full power is the worst case power requirement. If
that amount of power is available, no servers are throttled and the new server
is allowed to start up.
If the worst case power requirement is not available, power conservation
mode is activated. Power is reduced to the lower priority servers until enough
power is freed to start the new server.
• If enough power cannot be freed by reducing power to the existing servers,
the new server is not allowed to start up.
• If enough power is freed by reducing power to the existing servers, the
freed power is allocated to the new server and the server is allowed to start.
Power
Supply
#1
Power
Supply
#2
Power
Supply
#3
Blank
Slot
#4
Blank
Slot
#5
Blank
Slot
#6
Power Grid #1
Chassis DC Power Bus
Single Power Grid:
No protection against grid or power supply failure