sentences:  Given the dynamic nature of RAID-Z's stripe width, RAID-Z reconstruction must traverse the filesystem metadata to determine the actual RAID-Z geometry.This would be impossible if the filesystem and the RAID array were separate products, whereas it becomes feasible when there is an integrated view of the logical and physical structure of the data.Going through the metadata means that ZFS can validate every block against its 256-bit checksum as it goes, whereas traditional RAID products usually cannot do this.