Technology Insights

Ubuntu Linux Apache Error: [notice] child pid XXXX exit signal Segmentation fault (11)

I received the below error when troubleshooting an issue reported to me by a client regarding one of their intranet web sites not working properly. After some poking around I noticed that there were numerous segmentation faults being reported in the Apache error logs. I had previously set up the server to dump core files when there were segmentation faults within Apache so troubleshooting the error was fairly easy. It ended up being a connection issue with an AS400 that was down over the weekend at the company and I was able to verify this using the below information.

Technology Insights

Cacti Graph Templates Explained: RRDTool Graphing Solution

**Please Note This Article Is Paginated at the bottom and includes 4 pages**

How do I create Cacti Graph Templates? How do I display multiple data sources on one Cacti graph? What do all the Cacti options mean? What is a CDEF? I created a Cacti Graph but all of my data sources are displaying NAN, how do I troubleshoot that?

Cacti is a powerful RRDTool based graphing system typically used for graphing hardware and software data for historical reference. When I initially configured a Cacti Graph Template I found some of the options confusing but as you will see below they all make sense and typically the name explains each items function in a fairly easy way. Please post a comment if you have any further questions that are not answered or if I have made any answers feel free to use the contact form and point them out to me as I am trying to learn the best way to use Cacti just like everyone else. I repeat the same terms many times in this document simply for the fact to try and explain in detail what things mean. I did not want to start switching names with acronyms and vice verse to add confusion and to try and make this a very easy document to understand.