[HPDD-discuss] Understanding the lustre performance

I have 1 MDS, 2 OSS with 6 OSTs each and 4 Lustre Client. I have Hadoop setup with 1 Namenode and 3 datanode running on lustre clients. While I have 18GB input data in the form of many small files for wordcount, it took 1 hour time (striping: -1). I have been running this on Ethernet. I have ordered for Infiniband QDR which will reach in 2 weeks time. Anyone who tried it with Infiniband. What time it get reduce if I use infiniband switch and cable instead of Ethernet. Roughly how much lesser time and efficient it shows with Infiniband. Please do share your experience if you have used infiniband.