Owner's Manual

Power Management 327
If an administrator manually powers on the low priority server modules before
the higher priority ones, then the low priority server modules are the first
modules to have their power allocation lowered down to the minimum value,
in order to accommodate the higher priority servers. So after the available
power for allocation is exhausted, then CMC reclaims power from lower or
equal priority servers until they are at their minimum power level.
NOTE: I/O modules, fans, and iKVM (if present) are given the highest priority. CMC
reclaims power only from lower priority devices to meet the power needs of a higher
priority module or server.
Dynamic Power Supply Engagement
Dynamic Power Supply Engagement (DPSE) mode is disabled by default.
DPSE saves power by optimizing the power efficiency of the PSU’s supplying
power to the chassis. This also results in increased PSU life, and reduced heat
generation.
CMC monitors total enclosure power allocation, and moves the PSUs into
Standby state, causing the total power allocation of the chassis to be delivered
through fewer PSUs. Since the online PSUs are more efficient when running
at higher utilization, this improves their efficiency while also improving
longevity of the standby PSUs.
To operate remaining PSUs at their maximum efficiency:
• No Redundancy mode with DPSE is highly power efficient, with optimal
PSUs online. PSUs that are not needed are placed in standby mode.
•
PSU Redundancy mode with DPSE also provides power efficiency. At least
two supplies are online, with one PSU required to power the configuration
and one to provide redundancy in case of PSU failure.
PSU Redundancy
mode offers protection against the failure of any one PSU, but offers no
protection in the event of an AC grid loss.
•
AC Redundancy mode with DPSE, where at least two of the supplies are
active, one on each power grid, provides a good balance between efficiency
and maximum availability for a partially-loaded modular enclosure
configuration.
• Disabling DPSE provides the lowest efficiency as all six supplies are active
and share the load, resulting in lower utilization of each power supply.