Sorry, I posted in a panic pretty late.... I had the infinite wisdom to change my SATA SSD cache from btrfs to zfs. I stopped the array, clicked cache, changed the file system type to ZFS, clicked apply, then done. I did NOT bring the array back online and set it back to btrfs, apply -> done. Brought the array back online and am now seeing all drives in my array are using minimal data. Disk 3 still seems to have my Music folder in tact which I copied to a safe place for now. I stopped the array, posted my question above and went to sleep. When I got up this morning I brought the array up in maintenance mode and ran a btrfs check status in the gui. It shows it found errors: My non-cache drives are XFS and did not show any erros when running a status check.