== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 21:19:36 (1786324776)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       17264     1254040   2%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116        9784     1261520   1%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       24068     3582812   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       19532     3587404   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43600     7170216   1%  /mnt/lustre