== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 01:43:38 (1780811018)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      2210176       10624     2197504   1%  /mnt/lustre[MDT:0] 
lustre-OST0000_UUID      3771392       23552     3745792   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3771392       27648     3741696   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7542784       51200     7487488   1%  /mnt/lustre