Ganglia vs Zabbix: What are the differences?
What is Ganglia? Scalable distributed monitoring system. Ganglia is a scalable distributed monitoring system for high-performance computing systems such as clusters and Grids. It is based on a hierarchical design targeted at federations of clusters.
What is Zabbix? Track, record, alert and visualize performance and availability of IT resources. Zabbix is a mature and effortless enterprise-class open source monitoring solution for network monitoring and application monitoring of millions of metrics.
Ganglia and Zabbix can be primarily classified as "Monitoring" tools.
Zabbix is an open source tool with 493 GitHub stars and 182 GitHub forks. Here's a link to Zabbix's open source repository on GitHub.