Which status indicates that a hard drive is no longer being used by the RAID controller?

The status indicating that a hard drive is no longer being used by the RAID controller is known as "Inoperable." This status signifies that the drive has failed to function properly and, consequently, is not actively participating in the RAID array's operations. When a drive is marked as inoperable, the RAID controller will recognize it as dead or unusable, leading to a state where data redundancy may be compromised depending on the RAID level in use.

On the other hand, the status "Degraded" often refers to a condition where one or more drives in a RAID array are still functional but might not be performing optimally due to a failure of one or more drives. In this case, the RAID controller is still using the remaining operational drives to continue providing data access. "Initializing" suggests that a drive is being prepared for use within the RAID but is not yet ready. The term "Ready" indicates that a drive is available and operational, ready for use, but does not imply that it is already part of the array. Thus, the status of "Inoperable" is the most accurate choice, as it clearly denotes that the hard drive has been taken out of the RAID controller's management due to failure.