How to diagnose the cause of the server lag?

[Katawa]

I'm currently running a pretty big server with 4 of my friends and we are starting to get a lot of lag, sometimes the latency seem to spike, sometimes it drops the users from the game, how can I identify whether it's the problem with hardware performance or networking? We have a logistical bot abomination on Gleba with 3000 bots constantly in the air and a large base on Nauvis surrownded by the biters on all sides but the game reports 59.9-60 UPS, the server itself is a VM with 4 cores and 8Gb RAM running on modern hardware and it only reports 60% load, I tried making a circuit combinator clock, the server time seems to be with an 8% but the real problem is the frequent lag spikes and getting occasionally dropped from the game.

What should i look into so I could know whether I should go and nuke the Gleba bot base, or migrate the server to a different VPS provider?

[Atraps003]

Smokeping to monitor the network connection quality between the vps and the clients connecting to the vps. If the connection looks like this the lag will be terrible.

https://oss.oetiker.ch/smokeping/

[eris]

I have already asked refund, but I will buy again if this has been resolved?