An emergency power off accidentally occurs in a datacenter during a fire alarm test. On recovery, the server administrator notices that an external storage array is performing consistency checks on…

A redundant controller failure would trigger a controller failover event, not a post-recovery consistency check across all volumes.

A cold spare drive is an inactive standby that is not part of any active volume, so its failure would have no effect on volume consistency.

Storage arrays use write-back caching to buffer writes in fast volatile memory before committing them to disk, with a battery backup unit (BBU) maintaining power to that cache during outages so pending writes can be flushed safely. When the BBU has failed or faulted, a sudden power loss causes those cached writes to be lost, leaving volumes in a potentially inconsistent state. On recovery, the array automatically runs consistency checks across all volumes to detect and repair any data discrepancies caused by the unwritten cache data.

Failed cache memory modules would typically prevent the array from operating normally or would trigger hardware alarms, rather than specifically causing consistency checks after a power restoration.