== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 18:14:22 (1786572862)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       19820     1251484   2%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       13208     1258096   2%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       27204     3579816   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       17368     3589652   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       44572     7169468   1%  /mnt/lustre