"Are most drives retired without failing?" Yes, certainly. One can watch both SMART indicators as well as certain ZFS stats and catch a problem drive before i

"Are most drives retired without failing?" Yes, certainly. One can watch both SMART indicators as well as certain ZFS stats and catch a problem drive before it actually fails. I like to remove drives from zpools early because there is a common intermediate state they can fall into where they have not failed out but dramatically impact ZFS performance as they timeout/retry certain operations thousands and thousands of times.