== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 05:27:52 (1787045272)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       13796     1257508   2%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       18512     1252792   2%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       22612     3584352   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       20988     3585976   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43600     7170328   1%  /mnt/lustre