== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 14:53:36 (1785956016)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      2210048        7680     2200320   1%  /mnt/lustre[MDT:0] 
lustre-OST0000_UUID      3771392       23552     3741696   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3771392       25600     3741696   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7542784       49152     7483392   1%  /mnt/lustre