== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 12:30:22 (1786725022)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       11360     1259944   1%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       16328     1254976   2%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       24876     3582088   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       18728     3588236   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43604     7170324   1%  /mnt/lustre