== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 08:00:44 (1785412844)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       17612     1253692   2%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       10232     1261072   1%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       24092     3582928   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       19508     3587512   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43600     7170440   1%  /mnt/lustre