== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 16:38:26 (1786826306)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      2210176        8576     2199552   1%  /mnt/lustre[MDT:0] 
lustre-OST0000_UUID      3771392       24576     3744768   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3771392       24576     3744768   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7542784       49152     7489536   1%  /mnt/lustre