== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 06:47:14 (1787395634)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       19480     1251824   2%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       12084     1259220   1%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       22800     3584220   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       20752     3586268   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43552     7170488   1%  /mnt/lustre