Benchmarks challenges of XtraDB Cluster

We are running internally a lot of benchmarks on our recently announced Percona XtraDB Cluster, and I am going to publish these results soon.
But before that I wanted to mention that proper benchmark of distributed system comes with a lot of challenges.
I am saying that not to complain, but to make sure, if you are going to benchmark XtraDB Cluster yourself, there is a lot of things to take into account.

And it seems that one component, which was not much important before, now appears as critical peace, which easily can became bottleneck in the benchmarks – this is network.

In case of simple client-server setup, the network is not fully utilized.
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But as we start testing a cluster setup, the 1Gb network between client and switch is getting fully utilized by sysbench communication with 3 nodes.
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In this setup it does not make sense to increase number of nodes, as we will not be able to load them properly.

The solution would be to increase network capacity or add additional client boxes.

Now take into account that there is an internal network communication between nodes also, and that makes a network tuning as the critical part of a cluster setup. This is not something we paid much attention before.

The main conclusion of this post is that if you are going to benchmark a Percona XtraDB Cluster or just use it under intensive communication workload, pay an attention to network component. It is very easy that a client or a client network becomes bottleneck.

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