• One mirror pair shows out-of-sync
  • Controller may prompt for “rebuild mirror” or “synchronize”
  • OS boots, but apps crash or report corrupt files
  • One drive went stale or dropped out silently, then rejoined with outdated data
  • Controller is unsure which half of the mirror is valid
  • Silent corruption may have replicated to both disks if sync ran automatically
  • ❌ Don’t trigger a mirror rebuild without identifying the correct copy
  • ❌ Don’t assume newer timestamp = better data — it may be stale
  • ❌ Don’t rely on SMART data alone — it won’t catch logical mirror divergence

One wrong sync can overwrite your only clean copy. Let us verify the right half before they both go bad.