== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 21:20:25 (1787793625)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       11604     1259700   1%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       16372     1254932   2%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       24772     3581800   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       18780     3588240   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43552     7170040   1%  /mnt/lustre