Users Guide

Dynamic Power Supply Engagement
Default Redundancy Configuration
Power Budgeting For Hardware Modules
Viewing Power Consumption Status
Viewing Power Budget Status
Redundancy Status and Overall Power Health
Configuring Power Budget and Redundancy
Executing Power Control Operations
Redundancy Policies
Redundancy policy is a configurable set of properties that determine how CMC manages power to the
chassis. The following redundancy policies are configurable with or without dynamic PSU engagement:
• Grid Redundancy
• Power Supply Redundancy
• No Redundancy
Grid Redundancy Policy
The purpose of the Grid Redundancy policy is to enable a modular enclosure system to operate in a
mode in which it can tolerate power failures. These failures may originate in the input power grid, the
cabling and delivery, or a PSU itself.
When you configure a system for Grid Redundancy, the PSUs are divided into grids: PSUs in slots 1, 2, and
3 are in the first grid while PSUs in slots 4, 5, and 6 are in the second grid. CMC manages power so that if
there is a failure of either grid the system continues to operate without any degradation. Grid
Redundancy also tolerates failures of individual PSUs.
NOTE: Grid Redundancy provides seamless server operation despite failure of a whole power grid.
Hence, the maximum power is available to maintain Grid Redundancy when the capacities of the
two grids are approximately equal.
NOTE: Grid Redundancy is only met when the load requirements do not exceed the capacity of the
weakest power grid.
Grid Redundancy Levels
To configure Grid Redundancy, at least one PSU must be present in each grid. Additional configurations
are possible with every combination that has at least one PSU in each grid. However, to make the
maximum power available for use, the total power of the PSUs in each grid should be as close to equal as
practical. The upper limit of power while maintaining Grid Redundancy is the power available on the
weakest of the two grids. The following figure illustrates 2 PSUs per grid and a power failure on grid 1.
If CMC is unable to maintain Grid Redundancy, an email or SNMP alerts are sent to administrators if the
Redundancy Lost event is configured for alerting.
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