== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 04:15:57 (1786954557)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       19112     1252192   2%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       11656     1259648   1%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       23796     3583224   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       19776     3586992   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43572     7170216   1%  /mnt/lustre