== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 15:03:15 (1786820595)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       17772     1253532   2%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       10420     1260884   1%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       21676     3585316   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       21928     3585092   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43604     7170408   1%  /mnt/lustre