What does nclients option of performance evaluation tool pe of hbase does?

[#1]

Hbase provides pe tool for performance benchmarking. It has an option to mention the number of clients. Is it the number of Hbase region servers we have in the cluster?

[#2]

@Jay SenSharma
Hi, Can you please help me in this regard?

[#3 · Accepted solution]

Hi @Aishwarya Dixit, pe or "Performance Evaluation" is a tool based on MapReduce to test read/writes to HBase. nclients means that 10*nclients mappers will be started to run the supplied pe command. Example:

hbase pe randomWrite 2
...
2017-09-02 01:31:17,681 INFO  [main] mapreduce.JobSubmitter: number of splits:20

starts a MR job with 20 mappers and 1 reducer. So you can start with a small number like 1-3 to make sure HBase works as expected, and then increase it to about max number of mappers you can run on your cluster divided by 10. Of course you can use a larger number, but then mappers will run in multiple "waves".