== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 02:12:54 (1786428774)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       19272     1252032   2%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       11948     1259356   1%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       21972     3584936   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       21612     3584904   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43584     7169840   1%  /mnt/lustre