Dell PS-M4110 User Manual page 203

Additionally the capacity of each side must be enough to support the total power allocations for the
chassis to maintain AC redundancy. (For full AC Redundancy operation, ensure that a full PSU
configuration of six power supplies is available.)
– Resolution B: Check if all power supplies are properly connected to the two AC grids; power supplies in
side 1 need to be connected to one AC grid, those in side 2 need to be connected to the other AC grid,
and both AC grids need to be working. AC Redundancy is lost when one of the AC grids is not
functioning.
• Problem: The PSU state is displayed as Failed (No AC), even when an AC cord is connected and the power
distribution unit is producing good AC output.
– Resolution A: Check and replace the AC cord. Check and confirm that the power distribution unit
providing power to the power supply is operating as expected. If the failure still persists, call Dell
customer service for replacement of the power supply.
– Resolution B: Check that the PSU is connected to the same voltage as the other PSUs. If CMC detects a
PSU operating at a different voltage, the PSU is turned off and marked Failed.
• Problem: Dynamic Power Supply Engagement is enabled, but none of the power supplies display in the Standby
state.
– Resolution A: There is insufficient surplus power. One or more power supplies are moved into the
Standby state only when the surplus power available in the enclosure exceeds the capacity of at least
one power supply.
– Resolution B: Dynamic Power Supply Engagement cannot be fully supported with the power supply units
present in the enclosure. To check if this is the case, use the Web interface to turn Dynamic Power
Supply Engagement off, and then on again. A message is displayed if Dynamic Power Supply
Engagement cannot be fully supported.
• Problem: Inserted a new server into the enclosure with sufficient power supplies, but the server does not power
on.
– Resolution A: Check the system input power cap setting - it might be configured too low to allow any
additional servers to be powered up.
– Resolution B: Check for 110V operation. If any power supplies are connected to 110V branch circuits,
you must acknowledge this as a valid configuration before servers are allowed to power on. For more
details, see the power configuration settings.
– Resolution C: Check the maximum power conservation setting. If this is set then servers are allowed to
power on. For more details, see the power configuration settings.
– Resolution D: Check the server slot power priority of the slot associated with the newly inserted server,
and ensure it is not lower than any other server slot power priority.
• Problem: Available power keeps changing, even when the modular enclosure configuration hasn't changed
– Resolution: CMC 1.2 and higher versions have dynamic fan power management that reduces server
allocations briefly if the enclosure is operating near the peak user configured power cap; it causes the
fans to be allocated power by reducing server performance to keep the input power draw below System
Input Power Cap. This is normal behavior.
• Problem: 2000 W is reported as the Surplus for Peak Performance.
– Resolution: The enclosure has 2000 W of surplus power available in the current configuration, and the
System Input Power Cap can be safely reduced by this amount being reported without impacting server
performance.
• Problem: A subset of servers lost power after an AC Grid failure, even when the chassis was operating in the AC
Redundancy configuration with six power supplies.
– Resolution: This can occur if the power supplies are improperly connected to the redundant AC grids at
the time the AC grid failure occurs. The AC Redundancy policy requires that the left three power
supplies to be connected to one AC Grid, and right three power supplies to be connected to other AC
Grid. If two PSU are improperly connected, such as PSU3 and PSU4 are connected to the wrong AC
grids, an AC grid failure cause loss of power to the least priority servers.
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