I'm pretty sure I'm out of luck on this, but just wanted to double check. My 15 disk array (v 6.6.7) is a mix of 4 & 8 TB disks, all on ReiserFS. As is not uncommon with ReiserFS, I've been having write delays and other hiccups when the disks are nearly full, which most currently are. So I've been wanting to switch to XFS (for that and all the other reasons listed in the user guide and forums), but was looking to avoid the rsync method with an empty drive. I typically do a monthly parity build, so I though I'd just shut down the array, remove a disk from the array, reformat it in XFS, start the array and do a parity rebuild on the newly formatted drive. Rinse and repeat over several months to convert all the disks over to XFS (or faster if I replaced any disks). Oops. Didn't realize that reformatting a disk outside the array and then adding it back in would update the parity and not give the option for a parity rebuild (still not really sure why that's the case, would seem to be obvious to me). So I'm pretty sure I've lost all data on the drive I formatted to XFS, but just checking to see if there was any way to go back to the previous parity and rebuild the disk.