== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 02:57:29 (1786345049)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       16892     1254412   2%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       20144     1251160   2%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       26964     3579832   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       18696     3588240   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       45660     7168072   1%  /mnt/lustre