The &#x27;hidden&#x27; cost of traditional RAID for your home NAS:<p>I&#x27;ve learned the hard way that the &#x27;R&#x27; in traditional RAID truly does stand only for &quot;redundant&quot; and not &quot;reliable&quot;. Reliability in traditional RAID is predicated an complete, catastrophic failure of a drive such that it is either working wholly and completely or failing wholly and completely.<p>In a traditional RAID, for any failure mode in which a drive or its controller starts to report bad data before total failure, the bad data is propagated like a virus to the other drives. The corruption returned by a failing drive is lovingly and redundantly replicated to the other drives in the RAID.<p>This is the advantage of ZFS (or BTRFS). Blocks of data are checksummed and verified and corruption isolated and repaired. Yay for reliable data.