There are 3 kinds of log files:

1. error.log
2. access.log
3. debug.log

Any of them can be disabled by setting it to /dev/null or none in the Configuration. By default error.log and access.log are enabled. debug.log is only enabled if debugging is also enabled.

The error.log is the stderr of the netdata daemon and all plugins run by netdata.

So if any process in the netdata process tree writes anything to its standard error, it will appear in the error.log.

The access.log logs web requests. The format is:

DATE: ID: (sent/all = SENT_BYTES/ALL_BYTES bytes PERCENT_COMPRESSION%, prep/sent/total PREP_TIME/SENT_TIME/TOTAL_TIME ms): ACTION CODE URL

where:

• ID is the client ID. Client IDs are auto-incremented every time a client connects to netdata.
• SENT_BYTES is the number of bytes sent to the client, without the HTTP response header.
• ALL_BYTES is the number of bytes of the response, before compression.
• PERCENT_COMPRESSION is the percentage of traffic saved due to compression.
• PREP_TIME is the time in milliseconds needed to prepared the response.
• SENT_TIME is the time in milliseconds needed to sent the response to the client.
• TOTAL_TIME is the total time the request was inside netdata (from the first byte of the request to the last byte of the response).
• ACTION can be filecopy, options (used in CORS), data (API call).

Check the Tracing Options section.