> when we replaced drive+PS the tech may have picked the wrong direction to restore :X) In my experience, we lost RAIDs mostly to similar human error. RAID pro

> when we replaced drive+PS the tech may have picked the wrong direction to restore :X) In my experience, we lost RAIDs mostly to similar human error. RAID protects against a relatively infrequent but catastrophic failure. Since it's not constantly exercised, by the time it's needed, you might realize that the configuration or processes used aren't correct anymore. Other technologies force more automation and reduce human errors. E.g. if a disk fails in a distributed filesystem, the FS will have already re-replicated the data before anyone needs to swap drives (and without requiring a spare drive in every machine).