Listed below are SNMP enabled tools that offer a complete footprint, from collection to presentation.
MRTG - http://www.mrtg.org
The venerable Multi-Router Traffic Grapher. Excellent for small networks, this toolkit is great for monitoring your office uplinks, and can be hacked up to do other crazy voodoo if you're so inclined. The learning curve on this kit is a little sharp for the new user, but most Unix users will have little difficulty managing or customizing this.
- - billn says: If you try and scale this to handle more than 100 devices, I will tell Darwin where you live.
- - adamjacobmuller says: we succesfully use MRTG with rrdtool log format to log over 200 hosts, that includes logging load average; IMHO it works fine.
NetMRG - http://www.netmrg.net
Don't let the seeming similiarity to MRTG put you off, there's some serious meat in this tool kit.
- SNMP Abstraction layer: Manage polled objects separately by device type and platforms. This is an excellent way to keep SNMP from overwhelming the novice and even keeps the experts off the warpath. Polling targets will inevitably vary from platform to platform, and NetMRG's oid handling methods are very well designed to take the pain out of managing any network.
- Non-blocking, multi-threaded poller. If you have no idea what this means, just know it is a Good Thing(tm).
- Event and Threshold Triggers: Flexible monitoring customization provides the user with custom alerting and triggers based on polling data. Main interface is rocking more than 60% of capacity? Generate an email.
- Relatively straight forward interface. The novice may need to read up a bit, the expert will be up to speed in moments.
- Good support and well designed. Takes into account many business requirements for small to medium sized networks.
- Single poller architecture. All polled data is shoveled into RRDs.
- Natively, all data storage is via RRD.
- - billn says: I've got a patch in testing that'll feed to MySQL and recognize polling groups, letting you distribute your polling architecture.