I have a 4 node cluster setup. I'm benchmarking the setup using Rally. I have set the no. of "client" for a search operation in "track.json" to 12 with "target-throughput" of 2500. But the rally reported that it has performed only 2000 odd no. of operation against the set target of 2500 req/sec. I have increased the n0. of clients to 18, 20, 24, 30 and so on but the reported no. of operation for the search had not gone beyond 2000 req/sec.
Is this due to the limitation of server(co-ordinator) or rally or cluster setup?
I'm running benchmark co-ordinator on 4 core CPU, 16GB memory instance.