Before buying a VPS host, I usually check the reviews of other people using the VPS host. In particular, the line of the VPS host is what I am most concerned about. Because there are many foreign VPS hosting providers, but there are only a few computer rooms with fast access speeds from China. A VPS with poor lines and slow speed is not suitable for building a Chinese website.
If we find that our VPS server is abnormal, generally we can analyze it from the server logs to see if there is an IP source that does not follow the "rules". For example, we can use server log analysis tools: ngxtop and GoAccess to analyze the IP source, number of connections, error requests, browsers, traffic bandwidth, etc. in the statistical logs.
Smokeping is an open source and free network performance monitoring tool. It is mainly used to monitor network performance, including conventional ping, dig, echoing, curl, etc. The advantage of Smokeping is that it uses rrdtool to draw pictures, and the monitoring images are updated in real time and are beautiful.
