== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 12:08:41 (1789142921)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       17556     1253748   2%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       10036     1261268   1%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       22968     3583884   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       20644     3585900   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43612     7169784   1%  /mnt/lustre