When a block of data on a mirrored disk goes bad, mdadm won&#x27;t be able to fix it and often doesn&#x27;t even know that the data is bad.<p>Since there is a mirrored copy this a correct copy of your data but since there is no metadata or checksums, mdadm has no way to tell which is correct.<p>ZFS will silently detect the corruption and will rewrite the data restoring the duplicate copy of the data again.<p>All this works great without ECC RAM, recent studies of data corruption have shown that RAM is much more reliable then previously thought. ECCisnt needed for ZFS for home use.