Just encontered a bug when i tried to replace a failed drive. When pressing the replace button in the gui it would return the the error message drive to small. On further inspection i found that the replacement drive was being partitioned differently to my drives that were originaly in the pool. with the original drive being given 2G of swap space and the replacement drive was given 20G of swap space (Thus making it to small). I think ive worked around it in the meantime by manually making the partitions on the replacement drive and adding it to the pool but im not sure if what i experienced was a bug or not.