220-1201 Practice Question: That their RAID 5 array with three 2 TB drives is…

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

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  Initialize the missing drive in Disk Management.

  Why it's wrong here

  If a drive is reported as 'missing' from a RAID array, it indicates that the system, including the BIOS/UEFI and subsequently the operating system, cannot detect its presence at a fundamental hardware level. Disk Management is an operating system utility that can only interact with drives that have been successfully enumerated by the system's hardware and drivers. Therefore, attempting to initialize a drive that is not even detected by the system is impossible, as it will not appear within Disk Management for any configuration.

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  Replace the RAID controller.

  Why it's wrong here

  Replacing the RAID controller is a drastic and premature troubleshooting step when only a single drive is reported as missing from an array. A RAID controller failure typically manifests as issues affecting multiple drives, the entire array's functionality, or the controller's inability to boot. Basic physical checks, such as verifying power and data cables to the individual drive, should always precede component replacement, as these simple connection problems are far more common causes for a single drive not being detected.

• ✓

  Check the SATA cable and power connection to the missing drive.

  Why this is correct

  When a drive is reported as 'missing' from a RAID array, the most common and fundamental cause is a physical disconnection or a power delivery issue. Verifying the SATA data cable ensures proper communication between the drive and the RAID controller, while checking the power connection confirms the drive is receiving the necessary electrical current to spin up and operate. These simple, initial physical checks are the most logical and cost-effective troubleshooting steps before considering more complex hardware failures.

• ✗

  Rebuild the array using the remaining two drives.

  Why it's wrong here

  In a RAID 5 configuration, the array can tolerate the failure of a single drive due to distributed parity. However, attempting to 'rebuild' the array using only the *remaining* two drives when a third is merely 'missing' (and potentially recoverable) is highly destructive and will lead to data loss. This action would effectively create a new, degraded array from the remaining drives, overwriting any parity information that could be used to recover data from the *original* missing drive if it were to be reconnected. The correct procedure involves identifying and replacing the *failed* drive, then initiating a rebuild to restore redundancy.