== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 20:35:29 (1781224529)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       11120     1260184   1%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       16104     1255200   2%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       30244     3576524   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       13336     3593684   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43580     7170208   1%  /mnt/lustre