Upon identifying a potential cause of an issue with a RAID 5 array, especially when the array is making clicking noises that suggest a failing drive, the next critical step is to perform a full data backup. This ensures that data is preserved before any further troubleshooting steps are taken, such as replacing the failing drive.
RAID 5 provides fault tolerance, but ensuring data is backed up minimizes the risk of data loss during the repair process.
References:
CompTIA A+ Core 1 (220-1101) Exam Objectives, especially the sections dealing with storage devices and data backup and recovery principles, which would include strategies for dealing with potential drive failures in RAID arrays.
Best practices in data management and protection, emphasizing the importance of securing a backup before undertaking hardware replacements or repairs in storage arrays to prevent data loss.