== sanity test 56db: test 'lfs df -m' only shows MDT devices ========================================================== 00:00:09 (1770440409)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       21836     1249468   2%  /mnt/lustre[MDT:0]
lustre-MDT0001_UUID      1414116       19592     1251712   2%  /mnt/lustre[MDT:1]
lustre-OST0000_UUID      3833116       22168     3584852   1%  /mnt/lustre[OST:0]
lustre-OST0001_UUID      3833116       22388     3584632   1%  /mnt/lustre[OST:1]

filesystem_summary:      7666232       44556     7169484   1%  /mnt/lustre