What requirement must be met for a drive configuration to be considered fault-tolerant?

A drive configuration is considered fault-tolerant primarily when it utilizes a RAID (Redundant Array of Independent Disks) configuration. RAID is designed to enhance data availability and reliability through various levels of redundancy. By distributing data across multiple drives and implementing mechanisms such as mirroring or parity, RAID protects against drive failure.

For instance, in RAID 1, data is duplicated on two drives, ensuring that if one drive fails, the data remains accessible from the other drive. In RAID 5 and RAID 6, parity information is stored across multiple drives, allowing for data recovery if one or more drives fail.

While having spare drives, redundant drives, or identical drives can contribute to redundancy, they do not guarantee fault tolerance by themselves. RAID configurations are specifically designed to provide the necessary mechanisms for maintaining data integrity and availability in the event of hardware failures. Thus, implementing a RAID configuration is essential for achieving a fault-tolerant environment.