== sanity test 56db: test 'lfs df -m' only shows MDT devices ========================================================== 00:26:29 (1721881589)
UUID                   1K-blocks        Used   Available Use% Mounted on
lustre-MDT0000_UUID      1414116       21008     1266680   2% /mnt/lustre[MDT:0]
lustre-MDT0001_UUID      1414116       19452     1268236   2% /mnt/lustre[MDT:1]
lustre-OST0000_UUID      3833116       31044     3575976   1% /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       16496     3590524   1% /mnt/lustre[OST:1]

filesystem_summary:      7666232       47540     7166500   1% /mnt/lustre