== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 15:30:02 (1782243002)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       17420     1253884   2%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116        9800     1261504   1%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       29868     3576900   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       13732     3593204   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43600     7170104   1%  /mnt/lustre