== sanity test 56Db: test 'lfs df -m' only shows MDT devices ========================================================== 01:18:54 (1780463934)
UUID                   1K-blocks        Used   Available Use%  Mounted on
lustre-MDT0000_UUID      1414116       17436     1253868   2%  /mnt/lustre[MDT:0] 
lustre-MDT0001_UUID      1414116        9972     1261332   1%  /mnt/lustre[MDT:1] 
lustre-OST0000_UUID      3833116       20668     3586352   1%  /mnt/lustre[OST:0] 
lustre-OST0001_UUID      3833116       22912     3583884   1%  /mnt/lustre[OST:1] 

filesystem_summary:      7666232       43580     7170236   1%  /mnt/lustre