== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 16:07:06 (1779998826)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       11704     1259600   1%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       16256     1255048   2%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       28728     3577928   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       14852     3592084   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43580     7170012   1%  /mnt/lustre