== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 03:22:01 (1788938521)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      2210048        7936     2200064   1%  /mnt/lustre[MDT:0] 
lustre-OST0000_UUID      3771392       22528     3746816   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3771392       25600     3743744   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7542784       48128     7490560   1%  /mnt/lustre