== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 03:31:38 (1786087898)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       11188     1260116   1%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       16020     1255284   2%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       30080     3576828   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       13472     3593184   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43552     7170012   1%  /mnt/lustre