== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 02:27:34 (1786948054)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       11312     1259992   1%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       16228     1255076   2%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       24996     3582024   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       18556     3588100   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43552     7170124   1%  /mnt/lustre