Chassis Management Controller Version 2.0 for Dell PowerEdge VRTX User's Guide

By default, Dynamic Power Supply Engagement (DPSE) mode is disabled. DPSE saves power by optimizing the power efficiency of the PSUs that supply power to the chassis. This also results in increased PSU life, and reduced heat generation. To use this feature, you must have an Enterprise License.

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. As the online PSUs are more efficient when running at higher utilization, it improves their efficiency and longevity of the standby PSUs.

To operate remaining PSUs at their maximum efficiency, use the following power redundancy modes:

• PSU Redundancy mode with DPSE 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 a 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.
• Grid Redundancy mode with DPSE, where at least two PSUs are active, one on each power grid. Grid redundancy also balances the efficiency and maximum availability for a partially-loaded modular enclosure configuration.
• Disabling DPSE provides the lowest efficiency as all four supplies are active and share the load, resulting in lower utilization of each power supply.

• In a Power Supply Redundancy configuration, in addition to the PSUs required to power the enclosure, the enclosure always keeps an additional PSU powered on and marked Online. Power utilization is monitored and one PSU can be moved to Standby state on the basis of overall system load. In a four PSU configuration, a minimum of two PSUs are always turned on.

  Because an enclosure in the Power Supply Redundancy configuration always has an extra PSU engaged, the enclosure can accommodate the loss of one online PSU and still have enough power for the installed server modules. The loss of the online PSU causes a standby PSU to come online. Simultaneous failure of multiple PSUs may result in the loss of power to some server modules while the standby PSUs are turning on.

• In Grid Redundancy configuration, all PSUs are engaged when the chassis is turned on. Power utilization is monitored, and if system configuration and power utilization allows, PSUs are moved to the Standby state. Because the Online status of PSUs in a grid mirrors that of the other grid, the enclosure can sustain the loss of power to an entire grid with no interruption of power to the enclosure.

  An increase in power demand in the Grid Redundancy configuration cause the engagement of PSUs from the Standby state. This maintains the mirrored configuration needed for dual-grid redundancy.

  • NOTE: With DPSE in enabled state, if power demand increases in both the two Power Redundancy policy modes, the standby PSUs are brought Online to reclaim power.