One solution to add a redundancy to disk drives is the use of Redundant Array of Independent/Inexpensive Disks (RAID)
A large disk array comprising an arrangement of several independent disks that are organized to improve reliability and simultaneously increase performance.
How RAID improve reliability:
stores redundant information across the disks using a parity scheme or an error-correcting scheme.
Each byte of data may have a parity bit associated with it to check whether the number of bits in the byte that are set to 1 is even or add.
If the number of bits in the byte becomes corrupted, the new parity will not match the stored parity.
Similarly, if the stored parity bit become corrupted, it will not match the data in the byte.
Error-correcting schemes store two or more additional bits, and can reconstruct the original data if a single bit become corrupt.