== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 12:00:56 (1788364856)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      2210304       10112     2198144   1%  /mnt/lustre[MDT:0] 
lustre-OST0000_UUID      3771392       24576     3744768   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3771392       25600     3741696   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7542784       50176     7486464   1%  /mnt/lustre