== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 16:43:22 (1780346602)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       20360     1250944   2%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       13276     1258028   2%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       29880     3577084   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       13720     3593188   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43600     7170272   1%  /mnt/lustre