== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 04:20:59 (1788942059)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       17324     1253980   2%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116        9872     1261432   1%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       25008     3582012   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       18548     3588472   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43556     7170484   1%  /mnt/lustre