Ganglia and Its basics

Ganglia_basics

Ganglia 
- An open source scalable cluster performance monitoring tool
- Available almost on all OS

Data flow:
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Demon one per node/LPAR(Logical partition):
1. On every node a demon runs named as "gmond" - Ganglia monitor demon, which uses configuration /etc/gmond.conf
2. Say we have 3 nodes, on each node "gmond" runs and 3 of them share information such as 
  File access
  Network
  Web
3. One copy of web server, typically Apache (can be any other server) where "gmetad" - collects all info from "gmond"
4. "gmetad" uses configuration file - /etc/gmetad.conf
5. "gmetad" collects all the info and stores in "Round Robin database" using opensource tool "rrdtool"
6. Web UI picks data from Round Robin database and shows