<p>I track alot of things with RRD, eg, uptime, network throughput, etc. This works well when you can fit all the graphs on a single page, however, once you scale beyond a page it becomes difficult to use graphs to catch issues, you need to look at them to see that there is an issue, and if there is hundreds or thousands of graphs, that obviously isn't possible.</p>

<p>So, is there any standard way, or existing software for monitoring rrd databases for trend changes? Eg, every day, network traffic looks pretty much the same, if it spikes or dips dramatically in a single hour/day/week compared to the norm, I'd like to be alerted to it.</p>

<p>Or even just generic methods for finding changes in trends.</p>

You can read the RRD file directly, not just use the graphs generated. You might need to write your own app to do this, but the file format is an open standard so shouldn't be that difficult to get what you need.
RRD File Format