== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 19:26:20 (1786317980)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       17628     1253676   2%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       10208     1261096   1%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       22824     3584196   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       20728     3586292   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43552     7170488   1%  /mnt/lustre