Hot Spare Feature; Removing An Ac Power Supply Unit - Dell EMC VxRail P470 Owner's Manual

• Two 1100 W DC PSUs
CAUTION: For AC PSUs, use only PSUs with the Extended Power Performance (EPP) label on the back. Mixing PSUs from
previous generations of appliances can result in a PSU mismatch condition or failure to turn on.
NOTE: Dell EMC has optimized your appliance and recommends that you do not change any of these settings.
NOTE: When two identical PSUs are installed, power supply redundancy (1+1 – with redundancy or 2+0 – without redundancy)
is configured in system BIOS. In redundant mode, power is supplied to the appliance equally from both PSUs when Hot Spare is
disabled. When Hot Spare is enabled, one of the PSUs will be put into standby when appliance utilization is low to maximize
efficiency.
NOTE: If two PSUs are used, they must be of the same maximum output power.

Hot spare feature

Your appliance 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 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, then the redundant PSU is switched to the active state.
• If the load on the active PSU falls below 20 percent, 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 about iDRAC settings, see the Integrated Dell
Remote Access Controller User's Guide available at Dell.com/idracmanuals.

Removing an AC power supply unit

Prerequisites
CAUTION: The appliance needs one power supply unit (PSU) for normal operation. On power-redundant appliances, remove and
replace only one PSU at a time in a appliance that is powered on.
If applicable, unlatch and lift the optional cable management arm if it interferes with the power supply unit (PSU) removal. For information
about the cable management arm, see the appliance's rack documentation.
Follow the safety guidelines listed in the Safety instructions section.
Steps
1 Disconnect the power cable from the power source and from the PSU you intend to remove, and then remove the cables from the
strap.
2 Press the release latch and slide the PSU out of the chassis by using the PSU handle.
104 Installing and removing components