== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 08:30:02 (1781613002)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       17800     1253504   2%  /mnt/lustre[MDT:0] 
lustre-OST0000_UUID      3833116       22936     3584084   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       20580     3586440   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43516     7170524   1%  /mnt/lustre