== sanity test 56db: test 'lfs df -m' only shows MDT devices ========================================================== 00:18:11 (1763356691)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       21652     1249652   2%  /mnt/lustre[MDT:0]
lustre-MDT0001_UUID      1414116       19020     1252284   2%  /mnt/lustre[MDT:1]
lustre-OST0000_UUID      3833116       24348     3582672   1%  /mnt/lustre[OST:0]
lustre-OST0001_UUID      3833116       20224     3586796   1%  /mnt/lustre[OST:1]

filesystem_summary:      7666232       44572     7169468   1%  /mnt/lustre