To restore from a backup created using...
xtrabackup --login_path=xtrabackup --backup --rsync --target-dir=${BACKUP_DIR} --host=localhost --compress=lz4 2>${LOGFILE}
Do this...
xtrabackup --decompress --target-dir=${BACKUP_DIR}
xtrabackup --remove-original --target-dir=${BACKUP_DIR}
xtrabackup --prepare --target-dir=${BACKUP_DIR}
TODO