RAID 6E, also called as RAID 6 Enhanced, is a type of RAID 6 configuration with an integrated “hot-spare” disk. Backup disk in the system is the active part of the block.
The letter “E” in RAID 6E stands for “enhanced” or “extended” as it adds on or extends the capabilities of standard RAID 6 array. This is part of the overall RAID operations that distribute input/output across all disks, including disk backup, thus reducing the load on each disk and increasing the overall performance of the system. The spare drive in the system can only be used per array, not with other RAID arrays.
The “hot-spare” integrated with the configuration is a logical instance of the drive, not a physical instance. Spread across the disks, this spare drive consumes 10% of the space on each disk. Each spare drive / block is placed at the end of the array.