Users Guide

• Enables delivery of the total power allocation of the chassis through fewer PSUs.
• Increases the efficiency of the online PSUs as they run at higher utilization.
• Improves the efficiency and durability of the standby PSUs.
To operate remaining PSUs at their maximum efficiency:
• No Redundancy mode with DPSE is highly power efficient, with optimal PSUs online. PSUs that are
not needed are placed in standby mode.
• PSU Redundancy mode with DPSE also provides power efficiency. At least two supplies are online.
One PSU powers the configuration, while the other provides 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.
• Grid Redundancy mode with DPSE, where at least two of the 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. This
results in lower utilization of each power supply.
DPSE can be enabled for all three power supply redundancy configurations — No Redundancy, Power
Supply Redundancy, and Grid Redundancy.
• In a No Redundancy configuration with DPSE, the M1000e can have up to five power supply units in
Standby state. In a six PSU configuration, some PSU units are placed in Standby and stay unutilized to
improve power efficiency. Removal or failure of an online PSU in this configuration causes a PSU in
Standby state to become Online. However, standby PSUs can take up to 2 seconds to become active,
so some server modules may lose power during the transition in the No Redundancy configuration.
NOTE: In a three PSU configuration, server load may prevent any PSUs from transitioning to
Standby
• In a Power Supply Redundancy configuration, the enclosure always keeps an additional PSU powered
on and marked Online in addition to the PSUs required to turn on the enclosure. Power utilization is
monitored and up to four PSUs could be moved to Standby state depending on the overall system
load. In a six PSU configuration, a minimum of two power supply units are always turned on.
Since an enclosure in the Power Supply Redundancy configuration always has an extra PSU engaged,
the enclosure can withstand the loss of one online PSU. The enclosure can also 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 power supplies 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. The Online status of PSUs in a grid mirrors that of the other grid. Hence,
the enclosure can sustain the loss of power to an entire grid without interruption of power to the
enclosure.
An increase in power demand in the Grid Redundancy configuration causes the engagement of PSUs
from the Standby state. This maintains the mirrored configuration needed for dual-grid redundancy.
NOTE: With DPSE Enabled, the Standby PSUs are brought Online to reclaim power if power
demand increases in all three Power Redundancy policy modes.
Default Redundancy Configuration
The default redundancy configuration for a chassis depends on the number of PSUs it contains, as shown
in the following table.
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