== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 06:26:18 (1789467978)
UUID                   1K-blocks        Used   Available Use% Mounted on 
lustre-MDT0000_UUID      1414116       17656     1253648   2% /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       10344     1260960   1% /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       20800     3586080   1% /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       22808     3583848   1% /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43608     7169928   1% /mnt/lustre