What is the correct sequence of steps taken by the storage array when an AC...

Storage processors

Power

BIOS

SP Cache

Array

The Battery Backup Unit (BBU) provides power to the Storage Processor in the event that cabinet power is lost. The BBU is designed to power the SP long enough for the system to store SP cache content to the M.2 SSD device before powering down. The BBU includes sensors which communicate its charge and health status to the SP. In the event the BBU is discharged the SP will disable cache until the BBU has recharged. In the event the BBU has faulted or cannot sustain enough charge, an alert will be generated.

References: https://www.emc.com/collateral/white-papers/h15084-dell-emc-unity-introduction-to-the-platform.pdf