== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 02:16:09 (1784700969)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      2210176       12672     2195456   1%  /mnt/lustre[MDT:0] 
lustre-OST0000_UUID      3771392       24576     3744768   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3771392       25600     3743744   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7542784       50176     7488512   1%  /mnt/lustre