The RAID 6 array requires 4 disks at least, so the times that you can lose in RAID 6 vary based on the number of disks. Here, we take 4 disks on a RAID 6 as an example. In such one RAID, two disks will be used to store each data block, while the other two will be used to store parity blocks. In this case, you will lose 2 disks at most at the same time without data loss.