== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 08:47:23 (1789130843)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       13408     1257896   2%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       15852     1255452   2%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       21792     3585228   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       21820     3585200   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43612     7170428   1%  /mnt/lustre