== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 13:23:41 (1786209821)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       17716     1253588   2%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       10056     1261248   1%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       20676     3586344   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       22888     3583712   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43564     7170056   1%  /mnt/lustre