In order to detect when netdata is misbehaving, we run a concurrent task pinging netdata (wait-for-netdata-up) in the systemd unit.
If after a while, this task does not succeed, we stop the unit and mark it as failed.
You can control this deadline in seconds with this option, it's useful to bump it if you have (1) a lot of data (2) doing upgrades (3) have low IOPS/throughput.