The server is extremely laggy. Most players ping is between 120-250ms. The hardware shouldn’t be stressed, The CPU and RAM are both running at less than 50% utilization. And the in game tps is is a perfect 20tps.
Reproduction Steps
Yesterday the server was running perfectly
Today the server isn’t even playable due to poor connection.
nothing has been changed in the configuration, mods, etc…
Minecraft is mostly singlethreaded, so you need to measure CPU with single-core calculations in mind (doesn’t matter what hardware you have, Minecraft can still run poorly).
In general the official Vanilla server is poorly optimized, so you need to keep an eye on entity counts, and traveling too fast will slow down the server from generating too many chunks (keep the render distance around 10)
Im running the server on on purpur which intended for better performance, and i have mob spawns and such limited, same for the entity pathfinding, i haev limited lower than default values and the render distance is only on 12, yet not even one player can play at a time.
Yeah, Paper/Purpur can still get tanked by things in-game, though they do make things easier.
I would assume there’s some entities or farm kicking up some lag on the server.
I would suggest using the Spark plugin’s profiler to narrow down the source of any TPS drops.
I just installed spark, and i did a test with one player online, the CPU usage was at 18% and the mspt roughly 3ms. So the hardware is not even almost struggling, but still i have over 150ms ping when I should be normally getting roughly 30-50. and all other players are having the same issue.
Just a reminder that the actual CPU usage is around 18%*(num of cores), given that MC is mostly singlethreaded (anything over 100 usually leads to drops it TPS, but there can be exceptions at times).
The main metric you want to look at is TPS, as that’ll bugger pretty much everything else.
Network wise there could be some strange point A → point B issue that you can’t pick up on, really hard to tell with those.
Weird, the TPS and MSPT all look fine, even with a bunch of chunks/tile entities loaded, there aren’t any plugins that seem to be screaming “hey, I’m the problem” either.
My gut is leaning more towards “weird network voodoo” given the problem only started popping up recently. At least with Minecraft it’s still moderately playable at 250ms, but anything above that gets a bit touch-and-go.
I’d say check any Ethernet cables you have kicking around and double check that it’s running smooth locally (assuming the server is hosted locally).
That would narrow it down to being an external/possibly an ISP issue.
Or worse, it could be some unfix-able point A → point B issue that you can’t debug properly (which would hopefully fix itself eventually)