== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 01:12:57 (1782537177)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       17064     1254240   2%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       19952     1251352   2%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       32940     3574080   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       12596     3594424   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       45536     7168504   1%  /mnt/lustre