The first system that can operate as a backend store for metrics is InfluxDB. This is a special kind of database that stores time series data. Before you can use this feature, you will have to set up this database on a separate server. It is too heavy to run on the same GitLab machine. Instructions on how to configure this can be found at https://docs.gitlab.com/ee/administration/monitoring/performance/influxdb_configuration.html. When you enable InfluxDB metrics, it will set up a User Datagram Protocol (UDP) stream to the InfluxDB host that will carry all kinds of event information. You can fine-tune the connection pool size, the connection timeout, and so on to make sure that you don't generate too much data. After changing this setting, you will have to restart.