Comment by chungy

ZFS has built-in support for redundant disks (in fact, using a lower-level hardware or software RAID under ZFS is not recommended). This allows it to do fancy things like allocate files intelligently across stripes, rebuild a disk with only the data used by the file system (huge time saver), and be able to repair files on-the-fly that are damaged, or at worst, report what files cannot be repaired.