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MV3D is an open source virtual world simulation framework written in Python. It was designed with scalability in mind and aims to be able to distribute a world across as many servers as needed while dynamically balancing the load.
Shinken is a Linux/Windows monitoring tool in Python compatible with Nagios. The main goal of the program is to allows users to scale the load : it "cuts" the user's configuration into independent part and send it to workers.
Powow is an open-source TCP packets exchange mesh. It allows many TCP clients to connect to a "Powow cloud" (several instances of Powow), to exchange data. Powow is a TCP socket server like Palabre or Oregano.