== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 16:16:47 (1785961007)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       11512     1259792   1%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       16456     1254848   2%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       27840     3579096   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       15784     3591236   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43624     7170332   1%  /mnt/lustre