Graphing
Some useful links to explain the concepts of Graphing
Concepts
Cacti
Metrics
Ganglia
http://www.slashroot.in/introduction-ganglia-monitoring-and-graphing-tool
https://www.digitalocean.com/community/tutorials/introduction-to-ganglia-on-ubuntu-14-04
https://sachinsharm.wordpress.com/2013/08/17/setup-and-configure-ganglia-3-6-on-centosrhel-6-3/
What Ganglia does
Graph different properties of a server such as CPU,memory,load,etc
Compare the graphing trend of those properties with previous trend & identify which node or host is causing the issue easily from the trend.
Make custom metrics for graphing for different process.
Machines from different data centers which are part of one single cluster must be represented in that single cluster in a single interface.
Important points
Node : SINGLE machine sending data to Ganglia monitoring daemon. (All individual servers are nodes, can or can’t be part of a cluster)
Cluster : All nodes that are used for any particular purpose is a CLUSTER.
Grid : Collection of clusters is a GRID.
Parts of Ganglia Monitoring Tool
1. Gmond :
Ganglia Monitoring daemon (Service that needs to be installed on each & every node that needs to be monitored)
Sends data via XML over TCP & main configuration file :
/etc/gmond.conf
2. Gmetad :
Collects data from Gmond daemons & stores in RRD (Round robin database)
Main configuration file is /etc/gmetad.conf & should be installed on one node of each cluster
3. RRD tool :
Used by Ganglia to store data for visualization (graphing) & store data of particular time intervals & then graphs the same.
4. PHP Front-End :
A web interface on the master node that displays graphs and metrics from data in the RRD tool.
Configuration
http://linuxdrops.com/install-ganglia-monitoring-system-on-centos-rhel/
https://sachinsharm.wordpress.com/2013/08/17/setup-and-configure-ganglia-3-6-on-centosrhel-6-3/
http://a4amittripathi.blogspot.in/2014/01/how-to-configure-and-install-ganglia-in.html
http://www.ibm.com/developerworks/library/l-ganglia-nagios-1/