rate and irate are based on the counter type metrics.

rate(v range-vector) calculates the per-second average rate of increase of the time series in the range vector, for example, rate(http_request_total{method="post"}[1m])

  1. It’s a rate: total(now) - total(now - 1m) / 60s
  2. It’s an average rate: over 1m
  3. Average is calculated over the time range, that’s why range vector is required.
  4. It provides a smoother trend.

irate(v range-vector) calculates the per-second instant rate of increase of the time series in the range vector.

  1. similar to rate, but it’s an sensitive rate as it’s based on the last two data points.
  2. why calculate last two points still needs [1m] range? it’s for looking back when the data point is missed

rate_vs_irate

Reference:⌗