Which RAID configuration allows the system to operate with two disk failures?

RAID 6 is designed to provide fault tolerance by utilizing double parity, which allows the system to survive the failure of two disks simultaneously. This configuration spreads data and parity information across all disks in the array. In the event of a disk failure, the system can still operate by reconstructing the lost data using the remaining disks and the stored parity data. This makes RAID 6 an ideal choice for environments where data availability is critical, as it provides an additional layer of protection compared to other RAID levels.

To clarify the context, RAID 0 does not provide any redundancy and thus would fail if any single drive goes down, while RAID 1 mirrors data across two drives, surviving only one disk failure. RAID 5 offers single disk failure protection by using striping with parity but does not support multiple simultaneous disk failures, which is why RAID 6 is the preferred option for scenarios requiring resilience against two disk failures.