== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 12:35:36 (1783960536)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       19516     1251788   2%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       12056     1259248   1%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       21796     3585224   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       21756     3585264   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43552     7170488   1%  /mnt/lustre