Max and Min Values in Resource Graphs Incorrect when Applying Custom Range Greater Than 6 Days
Description
When performing resource graphs on a node interface, if the time frame of the resource graph is set to anything longer than 6 days (so 7 days or greater) the Min and Max values are incorrect.
For example, if I set a range as follows:
Start Time: March 11 10:00 AM End Time: March 17 10:00 AM
My Max In value is 112.45 M and my Max Out is 25.31 M.
If I then go in and change the range to include the previous range, but add another day as follows:
Start Time: March 10 10:00 AM End Time: March 17 10:00 AM
My Max In value is 84.32 M and my Max Out is 16.13 M. These values are obviously not correct.
The discrepancy here is due to the way that RRDTool-based storage consolidates values. For a timespan longer than 7 days, the more-precise 5-minute samples are not available to cover the entire timespan so consolidated hourly min and max values are displayed.
OpenNMS stores, by default:
1 week worth of 5 minute samples 1 month worth of hourly samples 1 year worth of daily samples
You can change the default settings inside datacollection-config.xml in the <rrd> tag at the top of the file. If you increase the number of samples kept for a particular RRA, you will also increase the disk space that the RRD files take up. Working as designed, marking as won't fix.
Issues like this will largely go away if we move to a different storage solution for our collection data.
Ron Roskens March 17, 2015 at 9:28 PM
Can you give a window snip of the graph and narrow it down to which specific graph is showing this issue?
When performing resource graphs on a node interface, if the time frame of the resource graph is set to anything longer than 6 days (so 7 days or greater) the Min and Max values are incorrect.
For example, if I set a range as follows:
Start Time: March 11 10:00 AM
End Time: March 17 10:00 AM
My Max In value is 112.45 M and my Max Out is 25.31 M.
If I then go in and change the range to include the previous range, but add another day as follows:
Start Time: March 10 10:00 AM
End Time: March 17 10:00 AM
My Max In value is 84.32 M and my Max Out is 16.13 M. These values are obviously not correct.