== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 09:03:47 (1786021427)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       10900     1260404   1%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       15888     1255416   2%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       22956     3584008   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       20648     3586288   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43604     7170296   1%  /mnt/lustre