Replace RRD with Cassandra as storage for collected performance data

by pulasthi for OpenNMS

OpenNMS is an enterprise grade network management and application platform developed under the Open Source model. The system was designed and engineered to provide the ability to monitor tens of thousands to ultimately unlimited devices with a single instance. In the current implementation of OpenNMS data is stored using RRD-Tool which has several limitations such as the I/O bottleneck and inability to change configurations such as resolution after they are defined on creation time. The aim of this project is to provide solutions to these limitations and improve the scalability and performance of OpenNMS by replacing RRD with Cassandra which is a highly scalable NoSQL database.