Users Guide

310 Power Monitoring and Power Management
iDRAC6 also supports power allocation to the PCIe expansion-cards for
applicable platforms. You can change the power allocated to the PCIe
expansion-cards installed in the expansion slot in the server. Two PCIe cards
can be installed in the applicable platforms. iDRAC dynamically adjusts the
power envelope close to the actual system requirement for the blade, adds the
power allocated for the expansion-card slot, and requests for the combined
power from CMC. For more information about expansion-cards, see the
Hardware Owner’s Manual available on the Dell Support site at
support.dell.com/manuals. For information about modifying the PCIe power
allocation, see "Viewing and Modifying PCIe Power Allocation" on page 313.
After the blade powers on, BIOS will boot and detect the actual power
consumption of the installed PCIe expansion cards. This occurs during POST.
iDRAC maintains the value used in the pre-init phase for the expansion-cards
if both cards are present. Once the updated value has been obtained based on
the currently installed PCIe cards, iDRAC combines that value with the
expansion card estimated power consumption and reports a new power value
for the overall blade. If CMC does not allocate enough power, iDRAC will
power off the blade. If CMC allocates enough power, BIOS is allowed to
continue booting and the server can start up.
For example, if 500W is the value iDRAC assumes during pre-init, this value
will be used unless you set a different value for the PCIe expansion slot
allocation. If you set a different value, this value will always be used during
pre-init. The value is preserved through AC power cycles. The input value will
then be compared to the number of cards installed when the system reaches
POST.