== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 21:20:02 (1787880002)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       17212     1254092   2%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116        9684     1261620   1%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       26924     3579984   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       16660     3589996   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43584     7169980   1%  /mnt/lustre