== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 04:30:00 (1789461000)
UUID                   1K-blocks        Used   Available Use% Mounted on 
lustre-MDT0000_UUID      1414116       17556     1253748   2% /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       10124     1261180   1% /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       22704     3584316   1% /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       20852     3585692   1% /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43556     7170008   1% /mnt/lustre