== sanity test 56db: test 'lfs df -m' only shows MDT devices ========================================================== 00:54:07 (1777006447)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       15852     1255452   2%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       21972     1249332   2%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       28652     3578368   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       15920     3591100   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       44572     7169468   1%  /mnt/lustre