User's Manual

256 Power Management
Dynamic Power Supply Engagement
Dynamic Power Supply Engagement (DPSE) mode is disabled by default.
DPSE saves power by using the minimum PSUs needed to power the chassis,
resulting in increased utilization of online PSUs and thus increasing their
efficiency. This results in increased PSU life, reduced heat generation, and
power savings by operating power supplies at more efficient power levels.
The CMC monitors total enclosure power allocation, and moves the PSUs
that are not required 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.
The system runs most efficiently with as few active PSUs as possible,
therefore:
• No Redundancy mode with DPSE is highly power efficient, with only the
minimum PSUs online. Unneeded PSUs are placed in standby mode.
•
PSU Redundancy mode with DPSE also provides power efficiency. At least
two supplies are active, 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 six 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.