23.3. Metrics Collection Considerations with Apache and SNMP

Three metrics show values of zero when monitoring an Apache instance with the SNMP module:
  • Bytes received for GET requests per minute
  • Bytes received for POST requests per minute
  • Total number of bytes received per minute
This is because of how SNMP interprets information from the request body. First, SNMP provides various length values for the request body and a GET request does not have a body, so GET responses are not calculated and, therefore, have a value of zero. Second, Apache does not calculate a request body size if there is request chunking.