== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 22:21:59 (1786760519)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       19540     1251764   2%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       12012     1259292   1%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       28156     3578864   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       15396     3591624   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43552     7170488   1%  /mnt/lustre