Infrastructure
From OpenCellID wiki
Contents
Servers
Software stack
Operating System
All OpenCellID servers are running with Ubuntu Linux 12.04 LTS.
Frontend
The web frontend uses Apache web server as a proxy for serving web requests to Tomcat.
The OpenCellID web application is running on Tomcat and is reading and writing cell measurements data to/from the MongoDB database backend.
Database Backend
The database backend, with a current 4.4 million cell towers and about 565 million measurements (1.1.2014), is a MongoDB database cluster with six servers.
Three servers are serving as MongoDB configuration servers and the other three servers are serving as database backend with one replication set spread across the three servers.