There are a few rules to stick to when naming metrics:
- Metric names must start with a letter
- Can only contain ascii alphanumerics, underscore and periods (other characters will get converted to underscores)
- Should not exceed 200 characters (though less than 100 is genearlly preferred from a UI perspective)
- Unicode is not supported
- We recommend avoiding spaces
Metrics reported by the Agent are in a pseudo-hierarchical dotted format (e.g. http.nginx.response_time). We say pseudo-hierarchical because we’re not actually enforcing a hierarchy or doing anything with it, but we have aspirations to use it to infer things about servers (e.g. “hey, I see hostA and hostB are reporting ‘http.nginx.*’, those must be web frontends”).