== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 05:45:52 (1787391952)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       17380     1253924   2%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116        9880     1261424   1%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       27048     3579972   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       16504     3590516   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43552     7170488   1%  /mnt/lustre