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Correlation among nodes

Correlations among different nodes are calculated. This is to give a measurement on how different resources work together. This is done by using the time series data that are already available, without other inputs (like transaction tracing or user defined topology) Pearson correlations among time series are calculated and the max of the absolute values of the intercorrelations among the time series of two nodes is assumed to be the correlation between two nodes (a bit of an overestimate). Currently, only simultaneous correlations within 1 and 15 minutes are considered.

Qualification for correlation​

In order to be considered by the correlation algorithm a node have to contain at leas one metric which:

  • produces at least 5 data points per week

  • has at least 4 changes of value per week

  • had data in the last three days

  • changed value in the last three days

Flat-liners, or metric which are mostly constant, are not considered for correlation.

If a node has no metrics suitable for correlation, but had those in the past, will have correlations of fading strength.

Correlations among nodes will be retuned by the correlation API only if two nodes have at least a pair of metrics with a correlation of 0.5 in absolute value.