== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 19:02:08 (1782255728)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       17400     1253904   2%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116        9952     1261352   1%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       21936     3584580   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       21656     3585280   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43592     7169860   1%  /mnt/lustre