== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 16:00:53 (1780344053)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       12076     1259228   1%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       16512     1254792   2%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       31128     3575892   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       12424     3594596   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43552     7170488   1%  /mnt/lustre