== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 23:38:45 (1784345925)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       12092     1259212   1%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       16848     1254456   2%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       20892     3586128   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       22652     3584368   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43544     7170496   1%  /mnt/lustre