== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 22:45:38 (1786761938)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       19500     1251804   2%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       12168     1259136   1%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       21972     3584880   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       21580     3585160   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43552     7170040   1%  /mnt/lustre