RAID 6 is a type of RAID that uses block-level striping with two parity blocks distributed across all member disks. It allows for two disk failures within the RAID set before any data is lost1. A minimum of four disks is requiredto create RAID 61. To increase the size of an existing RAID 6 array, the administrator can replace the array drives one at a time with larger drives and then expand the array. This way, the data and parity are rebuilt on each new drive and the array remains operational during the process2.