== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 18:31:30 (1787351490)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       11528     1259776   1%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116       16272     1255032   2%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       27912     3579108   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       15644     3591376   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43556     7170484   1%  /mnt/lustre