== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 17:22:03 (1787865723)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       13344     1257960   2%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       18132     1253172   2%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       31992     3574608   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       11564     3595456   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43556     7170064   1%  /mnt/lustre