User's Manual

Power Management 197
Power Management
Overview
The M1000e chassis ships with either three power supply units (PSUs) or six,
the maximum. If your chassis has three PSUs, you can add up to three more.
The PSUs supply power to the chassis and all the modules in the chassis:
CMC, IOM, iKVM, fans, front panel LCD and servers. The CMC manages
the power budget for all the chassis modules.
For AC redundancy to work in a six-PSU configuration, the three PSUs on the
left must connect to one AC power grid while the three on the right connect
to another. AC Redundancy is not available in a three-PSU configuration.
Each PSU helps the CMC manage the power distribution to the modules.
Power Budgeting for Hardware Modules
The CMC allocates power to some of the modules in the M1000e chassis
statically, and others dynamically. Static allocation means these modules are
assumed to be present and they are allocated a fixed amount of power.
Dynamic modules are given a power allocation by the CMC as they are
installed into the chassis.
The power budget for hardware modules in the chassis, including servers,
iDRACs on the servers, and IOMs, is allocated dynamically after
enumeration.
The chassis consists of compute and non-compute hardware modules.
Compute hardware modules include servers and iDRACs on the servers. Non-
compute hardware modules include the active CMC, standby CMC (if
present), iKVM, IOMs, front panel LCD, and fans. The power budget for
essential non-compute modules in the chassis is pre-allocated, which means
that the CMC will not decrease power to these modules to conserve power in
the event of a power loss.