I currently have Nagios installation for monitoring various systems (mainly Linux). I would like to implement some graphing tool for historical data (CPU, memory, disk usage, web server QPS etc). I've tried Nagiosgrpah however it's not reliable and very limited.
I would like to try Cacti but I'm not sure what's the recommenced/secure way to pull the data from the remote servers. Is there some agent that needs to be installed on the monitored machine?
I've came across other tools like Ganglia and Graphite.
Could you recommend any of these tools in my case?