== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 09:40:40 (1787838040)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       16916     1254388   2%  /mnt/lustre[MDT:0] 
lustre-OST0000_UUID      3833116       20404     3586616   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       22604     3584416   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43008     7171032   1%  /mnt/lustre