RAID: Level 6

RAID 6 extends RAID 5 by adding an additional layer of redundancy through a second parity block, allowing for the failure of two disks simultaneously.

Like RAID 5, data and parity are distributed across all disks, but the second parity calculation increases the complexity and time required for writes. This enhanced fault tolerance makes RAID 6 a reliable choice for critical systems, especially those with large arrays of high-capacity disks where multiple failures are more likely.

The configuration requires at least $4$ disks, and the usable capacity is the total capacity of all disks minus two parity disks. Although write performance is slower than RAID 5, read speeds remain high, and the additional parity makes it highly reliable for systems that prioritize data integrity.

RAID 6 is often used in enterprise environments, such as large-scale storage systems, virtualization platforms, and mission-critical applications where downtime must be minimized. However, rebuilding a failed array can still be resource-intensive, and administrators should ensure proper hardware support for parity calculations.