== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 18:12:03 (1786831923)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       17432     1253872   2%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116        9900     1261404   1%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       32020     3575000   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       11532     3595488   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43552     7170488   1%  /mnt/lustre