Integrated Dell Remote Access Controller 9 Version 3.21.21.21 User's Guide

Power capping in Blade servers

Before a blade system powers up, iDRAC provides the power requirements of the blade system to the chassis manager based on limited hardware inventory information. If the power consumption increases over time and if the system consumes power near its maximum allocation, iDRAC may request CMC to increase the maximum potential power, which results in an increase in the power envelope. iDRAC requests CMC only to increase the power delivery, however, it does not request CMC to reduce the power delivery if the consumption decreases. If sufficient power is not allocated, the blade system does not power on.

After the system is powered on and initialized, iDRAC calculates a new power requirement based on the actual hardware configuration. The system stays powered on even if the CMC fails to allocate new power request.

CMC reclaims any unused power from lower priority servers and allocates that power to a higher-priority infrastructure module or a server.