sentences:  CRYPTO does not provide redundancy.Some filesystems, such as btrfs, and ZFS/OpenZFS (with per-dataset copies=1|2|3 property), support creating multiple copies of the same data on a single drive or disks pool, protecting from individual bad sectors, but not from large numbers of bad sectors or complete drive failure.This allows some of the benefits of RAID on computers that can only accept a single drive, such as laptops.