cassandra_os_recent_cpu_load_ratio reporting different metrics to sar and OS cpu metric

[chrisjmiller1]

Hi folks,

We are seeing a mismatch between what cassandra_os_recent_cpu_load_ratio and sar is reporting.

Here's the sar data for the same period:

03:40:01 AM     CPU     %user     %nice   %system   %iowait    %steal     %idle
...
06:05:03 AM     all     37.65      0.00      3.90      7.63      0.88     49.93
06:10:01 AM     all     34.33      0.00      3.71      7.77      0.74     53.46
06:15:01 AM     all     31.85      0.00      3.41      6.09      0.62     58.03
06:20:01 AM     all     27.23      0.00      3.10      5.88      0.50     63.30
06:25:03 AM     all     34.87      0.00      2.85      1.49      0.45     60.34
06:30:01 AM     all     28.96      0.00      2.63      1.24      0.33     66.84
06:35:03 AM     all     30.06      0.00      2.69      1.26      0.36     65.63
06:40:01 AM     all     29.72      0.00      2.67      1.03      0.35     66.23
06:45:01 AM     all     30.58      0.00      2.60      1.14      0.32     65.37
06:50:01 AM     all     28.70      0.00      2.66      1.01      0.33     67.30
06:55:03 AM     all     30.19      0.00      2.66      1.16      0.32     65.67
07:00:01 AM     all     29.78      0.00      2.51      1.06      0.28     66.37
07:05:03 AM     all     30.15      0.00      3.05      1.31      0.45     65.05

Is there a reason why the metrics are so different?

We're using Cassandra exporter 0.9.14.

Thanks,

Chris.