RAID 6 is a data storage technology that uses multiple hard drives to provide redundancy and improve performance. It requires a minimum of four drives and can withstand the failure of up to two drives without losing data. This is achieved by distributing data and parity information across all drives, allowing for recovery in case of a failure. The parity information in RAID 6 is calculated using a complex algorithm, which ensures that even if two drives fail, the data can still be reconstructed. This makes RAID 6 a popular choice for businesses and individuals who prioritize data safety and reliability.