== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 23:23:33 (1786764213)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       11548     1259756   1%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       16352     1254952   2%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       23700     3583012   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       19868     3587068   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43568     7170080   1%  /mnt/lustre