== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 00:32:12 (1788841932)
UUID                   1K-blocks        Used   Available Use% Mounted on 
lustre-MDT0000_UUID      1414116       11164     1260140   1% /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       16024     1255280   2% /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       31020     3575552   1% /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       12576     3594360   1% /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43596     7169912   1% /mnt/lustre