== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 01:26:01 (1787721961)
UUID                   1K-blocks        Used   Available Use% Mounted on 
lustre-MDT0000_UUID      1414116       13112     1258192   2% /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       18028     1253276   2% /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       22740     3584280   1% /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       20864     3586156   1% /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43604     7170436   1% /mnt/lustre