User's Manual

220 Power Management
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 insufficient
power is available for the worst-case power need of all servers in the chassis. If
enough power cannot be freed by reducing the allocated power of the lower
priority servers, the new server may not be allowed to power up.
The highest amount of 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, then no servers are
allocated power that is less than the worst-case power needed and the new
server is allowed to power up.
If the worst-case power requirement cannot be met, power is reduced to the
lower priority servers until enough power is freed to power up the new server.
• If enough power cannot be freed by reducing power to the existing servers,
the new server is not allowed to power up.
Power
Supply
#1
Power
Supply
#2
Power
Supply
#3
Empty
Slot
#4
Empty
Slot
#5
Empty
Slot
#6
Power Grid #1
Chassis DC Power Bus
Single Power Grid:
No protection against grid or power supply failure