== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 09:21:30 (1789132890)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       17332     1253972   2%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116        9856     1261448   1%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       28096     3578924   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       15520     3591500   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43616     7170424   1%  /mnt/lustre