== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 20:24:59 (1787876699)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       11308     1259996   1%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       16248     1255056   2%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       22584     3584016   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       20980     3586040   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43564     7170056   1%  /mnt/lustre