== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 01:42:49 (1786772569)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       19456     1251848   2%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       12016     1259288   1%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       30816     3575756   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       12768     3594252   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43584     7170008   1%  /mnt/lustre