Nagios XI (This is a commercial implementation of Nagios) can graph as well as send alerts based on threshold conditions. I am not able to understand the difference between Nagios and Cacti. Any idea regarding the differences between the two?
I would prefer not duplicating effort.
Nagios is a monitoring and alerting system, which has graphing capability (if you pay for it).
Cacti is a graphing system, which does not have alerting capabilities (at least not years ago when I used it last, and there's no mention of it on the Cacti site).
The two are related (and often paired to avoid paying for the commercial Nagios implementation), but they serve different core functions: Nagios (without graphing) looks at the Now (current condition and alarms), Cacti looks at the long-term history.
Simple: Nagios was built with alerting first. Cacti was built with graphing first.
Both have addons that will enable the functionality of the other, but it boils down to what you want. If you already have a monitoring solution, and just want performance graphs Cacti might make sense. If you want a single unified solution with an emphasis on monitoring, Nagios might make sense.
Cacti can alert based on thresholds using the thold plugin, but Nagios can do so much more (passive checks, handle flapping more gracefully, team-based alerts that are "time of day" aware, etc.) Cacti also relies on SNMP or WMI to gather what it needs. Nagios can do SSH, WMI, SNMP, and it also has agents for Windows that can do some pretty powerful stuff compared to Cacti.
Not bashing Cacti (I've deployed it before), but I prefer alerting to be the focus of my unified alerting/graphing solution.
Both are using for monitoring servers and Services. Simply Nagios is use for check service and Servers availability and send alert. Cacti gives reach graphs facilities. you can use both monitoring tools in your wide Infrastructure for make simple and fast. Use Nagios to check Services (Aapche, Servers, Network, Qmail, MySQL, MemCached, Disk Space, Memory etc) Availability and Manage Alerts. Use Cacti to make Services (Apache, MySQL, MemCached, Redis, etc) performance graphs.
Nagios Core is meant to be a simple but powerful monitoring engine. Cacti is more for visual graphing and they work well together. Nagios XI uses Nagios Core as the monitoring and alerting engine. Nagios XI also has visual graphing and trending capabilities. If you have even the smallest budget Nagios XI is the way to go. If you don't have a budget Nagios Core and Cacti are the way to go.
What it boils down to is Cacti was built before Nagios was great at graphing. But with Nagios XI, there is no need for cacti.
