Users Guide

Table 37. Default Redundancy Configuration
PSU Configuration Default Redundancy Policy Default Dynamic PSU Engagement Setting
Six PSUs Grid Redundancy Disabled
Three PSUs No Redundancy Disabled
Grid Redundancy
In Grid Redundancy mode with six PSUs, all six PSUs are active. The three PSUs on the left must connect
to one input power grid, while the three PSUs on the right connect to another power grid.
CAUTION: To avoid a system failure and for Grid Redundancy to work effectively, there must be a
balanced set of PSU properly cabled to separate grids.
If one grid fails, the PSUs on the functioning grid take over without interruption to the servers or
infrastructure.
CAUTION: In Grid redundancy mode, you must have balanced sets of PSUs (at least one PSU in
each grid). If this condition is not met, Grid redundancy may not be possible.
Power Supply Redundancy
When power supply redundancy is enabled, a PSU in the chassis is kept as a spare, ensuring that the
failure of any one PSU does not cause the servers or chassis to power-down. Power Supply Redundancy
mode requires up to four PSUs. Additional PSUs, if present, are utilized to improve power efficiency of the
system if DPSE is enabled. Subsequent failures after loss of redundancy may cause the servers in the
chassis to power down.
No Redundancy
Power in excess of what is necessary to power the chassis is available, even on a failure, to continue to
power the chassis.
CAUTION: The No Redundancy mode uses optimum PSUs when DPSE is enabled for the
requirements of the chassis. Failure of a single PSU could cause servers to lose power and data in
this mode.
Power Budgeting For Hardware Modules
CMC offers a power budgeting service that allows you to configure power budget, redundancy, and
dynamic power for the chassis.
The power management service enables optimization of power consumption and re-allocation of power
to different modules based on demand.
The following figure illustrates a chassis that contains a six-PSU configuration. The PSUs are numbers 1-6,
starting on the left-side of the enclosure.
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