System information

Dell
PowerEdge M1000e Technical Guide 34
If power consumption demands exceed available power, the enclosure throttles back the power
supplied to blades as prioritized in the CMC. The blades will not shut down; rather they will slow
down if necessary; Dell designed the system this way on purpose, in response to customer feedback
that they did not want the blades to shut themselves down under any condition. I/O modules, on the
other hand, will shut down prior to permanent damage, as they are less tolerant to power variation
than the blade server hardware.
The M1000e is compliant with the PMBus Specification 1.1, using this power management standard
for status, measurement, and control. The M1000e power supplies continuously monitor AC input
current, voltage and power, enabling exposure of data to Dell™ OpenManage™ IT Assistant or to other
enterprise-level management tools. Real-time power consumption is viewable per system.
Figure 21. PMBus Communication Channels
Each PSU contains a FRU and a microcontroller. The FRU stores and transfers information about the
PSU across the PMBus (I2C bus):
• Vendor part number
• Revision serial number
• Power capability
The microcontroller performs the following functions:
• Control for the main power regulator
• Reports PSU status across the PMBus
o Input/Output Voltage/Current
o AC power consumption
o DC power consumption
o Error status
o Individual Status Signals from the PSU to the CMC
o AC Good
o DC Good
o PSU Present Alert
VMware has included consuming the "current power consumption" and "current power cap/limit"
retrieval through Dell-specific IPMI commands through iDRAC in eleventh generation servers. They
are using this to report the total power consumed by the server and also using this as part of their
calculations to determine/approximate the VM-level power. Unfortunately, there is no integration as
yet of generating the view/consolidation of power attributes across all the blades in a chassis, such