The median is the value separating the higher half from the lower half of a data sample (a population or a probability distribution). For a data set, it may be thought of as the "middle" value.
median is not an accurate average. However, it eliminates all spikes, by sorting
all the values in a period, and selecting the value in the middle of the sorted array.
Netdata also supports
trimmed-median, which trims a percentage of the smaller and bigger values prior to finding the
median. The following
trimmed-median functions are defined:
trimmed-median is an alias for
how to use
Use it in alarms like this:
lookup: median -1m unaligned of my_dimension
warn: $this > 1000
median does not change the units. For example, if the chart units is
requests/sec, the result
will be again expressed in the same units.
It can also be used in APIs and badges as
&group=median in the URL. Additionally, a percentage may be given with
&group_options= to trim all small and big values before finding the median.
Examining last 1 minute
successful web server responses: