== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 21:10:33 (1785978633)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       17660     1253644   2%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       10112     1261192   1%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       28208     3578308   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       15412     3591524   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43620     7169832   1%  /mnt/lustre