Graphite

collectd 5.1, RRD vs Graphite graph

Asked by Manish Sapariya

Hi,
I am evaluating collectd+graphite to migrate from my munin based monitoring. In the literature of graphite I read that graphite is using its own database. To see if I should keep using RRDs or move to graphite's native database, I exported RRDs as well as graphite data from collectd using its native write_graphite plugin.

The problem is that all CPU graphs are rendered as counter graph instead of guage value for graphite data source. The RRD graph's are rendered as expected.

Some of the disk graph's are rendered correctly for both RRD and Graphite data source.

How do I isolate the problem to graphite or collectd's write_graphite plugin?
Please let me know if I need to share graph image or whisper/RRD data.

Thanks and Regards,
Manish

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Michael Leinartas
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Best Michael Leinartas (mleinartas) said : 		#1

Generally with collectd cpu graphs you'll first derive the counter values to get per-time period counts, and then graph the ratio of each cpu type to the total. Many (myself included) prefer to have the write_graphite plugin pre-derive the COUNTER and DERIVE values before storage since they're almost always viewed derived.. You can do this by turning StoreRates on to true (http://collectd.org/wiki/index.php/Plugin:Write_Graphite)

With pre-derived values, I graph CPU like this (note I also have AlwaysAppendDS true as well)
asPercent(collectd.server1.cpu.0.cpu.*.count)
When one parameter is passed to asPercent, all of the series will be added for a total and then each will be divided by that total returning a percent. An alternate method is to just graph that wildcard in stacked mode (the y axis numbers wont be useful in that case though).

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Manish Sapariya (manish-sapariya) said : 		#2

Michael,
Thanks for the information. I have few more queries based on you answer.

1. What is the recommended StoreRates, true or false?
2. What benefits I get if I set it false and modify the graph function as suggested by you?

Regards,
Manish

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Manish Sapariya (manish-sapariya) said : 		#3

Thanks Michael Leinartas, that solved my question.

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Jonathan Kinred (jonathan-kinred) said : 		#4

Posting on this old thread because it's on of the first hits in Google when trying to work out exactly what StoreRates does and whether it's better to set it to true or false.

StoreRates simply calculates a GAUGE value for COUNTER values.

As Michael mentioned above this is almost always what you want and will simplify the query you write to graph the data. For this reason, my recommendation is to set it to true.