Dell PowerEdge VRTX User Manual page 171

chassis to maintain AC redundancy. (For full AC Redundancy operation, make sure that a full PSU
configuration of four power supplies is available.)
– Resolution B: Check if all power supplies are properly connected to the two AC grids; power supplies in
side 1 must be connected to one AC grid, those in side 2 must be connected to the other AC grid, and
both AC grids must 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 for 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 the maximum power conservation setting. If this is set, then this issue occurs.
For more details, see the power configuration settings.
– Resolution C: Check for the server slot power priority of the slot associated with the newly-inserted
server, and then ensure it is not lesser than any other server slot power priority.
• Problem: Available power keeps changing, even when the modular enclosure configuration has not changed.
– Resolution: CMC has 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: <number>W is reported as the Surplus for Peak Performance.
– Resolution: The enclosure has <number>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 four 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 two power supplies
be connected to one AC grid, and right two power supplies be connected to other AC grid. If two PSUs
are improperly connected, such as PSU 2 and PSU 3 are connected to the wrong AC grids, an AC grid
failure cause loss of power to the least priority servers.
• Problem: The least priority servers lost power after a PSU failure.
– Resolution: To avoid a future power supply failure causing servers to power off, make sure that the
chassis has at least three power supplies and is configured for the Power Supply Redundancy policy to
prevent PSU failure from impacting server operation.
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