== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 06:02:23 (1787479343)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       11644     1259660   1%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       16252     1255052   2%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       29032     3577540   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       14564     3592288   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43596     7169828   1%  /mnt/lustre