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From Marcos Luis Ortiz Valmaseda <marcosluis2...@gmail.com>
Subject Re: Inconsistent performance numbers with increased nodes
Date Fri, 19 Apr 2013 19:26:42 GMT
Regards, Alex.
We need more information to be able to get you a good answer:
- Java version
- JVM tuning configuration
- Hadoop JT, DN, NN configuration
- Network topology
- Network speed for the cluster
- Hardware properties for all nodes in the cluster

Hadoop is an actual scalable system, where you can add more nodes and the
performance should be better, but there are some configurations which can
downgrade its performance.

Another things is:
Which platform are you using for the benchmark?
There is an amazing platform developed by Jason Dai from Intel called
Hibench, which is great for this kind of work.[1][2]

With all this information, I think that we can help you to find the root
causes behind the performance of the cluster.

[1] https://github.com/intel-hadoop/HiBench

2013/4/19 Alex O'Ree <spyhunter99@gmail.com>

> Hi I'm running a 10 data node cluster and was experimenting with
> adding additional nodes to it. I've done some performance bench
> marking with 10 nodes and have compared them to 12 nodes and I've
> found some rather interesting and inconsistent results. The behavior
> I'm seeing is that during some of the 12 node bench runs, I'm actually
> seeing two different performance levels, one set at a different level
> than 10 nodes, and another at exactly the performance of a 10 node
> cluster. I've eliminated any possibility of networking problems or
> problems related to a specific machine. Before switching to a 12 node
> cluster, the initial cluster was destroyed, rebuilt and the dataset
> was added in. This should have yielded an evenly balanced cluster
> (confirmed through the web app)
> So my question is, is this an expected behavior or is something else
> going on here that I'm not aware of. For reference, I'm using 1.0.8 on
> CentOS 6.3 x64

Marcos Ortiz Valmaseda,
*Data-Driven Product Manager* at PDVSA
*Blog*: http://dataddict.wordpress.com/
*LinkedIn: *http://www.linkedin.com/in/marcosluis2186
*Twitter*: @marcosluis2186 <http://twitter.com/marcosluis2186>

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