Owners Manual

Hot spare feature
Your system supports the hot spare feature that significantly reduces the power overhead associated with power supply unit
(PSU) redundancy.
When the hot spare feature is enabled, one of the redundant PSUs is switched to the sleep state. The active PSU supports 100
percent of the system load, thus operating at higher efficiency. The PSU in the sleep state monitors output voltage of the active
PSU. If the output voltage of the active PSU drops, the PSU in the sleep state returns to an active output state.
If having both PSUs active is more efficient than having one PSU in the sleep state, the active PSU can also activate the
sleeping PSU.
The default PSU settings are as follows:
● If the load on the active PSU is more than 50 percent of PSU rated power wattage, then the redundant PSU is switched to
the active state.
● If the load on the active PSU falls below 20 percent of PSU rated power wattage, then the redundant PSU is switched to
the sleep state.
You can configure the hot spare feature by using the iDRAC settings. For more information, see the iDRAC User’s Guide
available at Dell.com/idracmanuals.
Removing a power supply unit blank
Prerequisites
Follow the safety guidelines listed in Safety instructions.
Steps
If you are installing a second PSU, remove the PSU blank in the bay by pulling the blank outward.
CAUTION:
To ensure proper system cooling, the PSU blank must be installed in the second PSU bay in a
non-redundant configuration. Remove the PSU blank only if you are installing a second PSU.
Figure 92. Removing a power supply unit blank
Next steps
Install the second PSU.
Installing a power supply unit blank
Prerequisites
1. Follow the safety guidelines listed in Safety instructions.
2. Install the power supply unit (PSU) blank only in the second PSU bay.
Steps
Align the PSU blank with the PSU slot and push it into the PSU slot until it clicks into place.
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Installing and removing system components