== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 23:13:02 (1787454782)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       17508     1253796   2%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       10028     1261276   1%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       21684     3585280   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       21924     3585068   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43608     7170348   1%  /mnt/lustre