== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 13:20:00 (1786468800)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      2210304       10240     2198016   1%  /mnt/lustre[MDT:0] 
lustre-OST0000_UUID      3771392       23552     3740672   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3771392       26624     3742720   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7542784       50176     7483392   1%  /mnt/lustre