Redundancy policies, Grid redundancy policy – Dell POWEREDGE M1000E User Manual

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Viewing Power Budget Status
Redundancy Status and Overall Power Health
Configuring Power Budget and Redundancy
Executing Power Control Operations

You can execute the following power control operation for the chassis, servers, and IOMs.

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.

Figure 5. PSUs per grid and a power failure on grid 1

In the event of a single PSU failure in this configuration, the remaining PSUs in the failing grid are marked as Online. In
this state, any of the remaining PSUs can fail without interrupting operation of the system. If a PSU fails, the chassis

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