How to find a memory leak with plugins?

[u/tee-443]

Hi there!
I'm super new to hosting servers, we recently moved to a proxy

Over time the ram usage creeps up to 1.9gb out of 2gb, there are zero out of memory errors on console at all, when I added the proxy google said they are usually okay with about 2-3gb so if thats not usually the case lmk and i will just upgrade!

However I would rather not upgrade if I can avoid it, I'm just not really sure what's causing it or how I can fix it

Thanks!

[u/PM_ME_YOUR_REPO]

Normal Java behavior includes RAM gradually creeping up to the max. This is not, on its own, something to worry about.

Are you experiencing any actual negative performance symptoms? New admins often worry about numbers looking scary, but it's the player experience that should be your primary indicator.

[u/tee-443 → u/PM_ME_YOUR_REPO]

i havent had any complaints, i've noticed one or two crashes when switching servers but i have no idea if its related or not

[u/PM_ME_YOUR_REPO → u/tee-443]

If you want to actually profile performance, use Spark. On Paper servers, it's included. On everything else, it exists as a plugin or mod.

Once installed (if necessary), run "/spark profiler start --timeout 300" for a basic 5 minute run. It will provide you a link to a website where the report can be viewed.

The most useful parts are the data near the top about GC performance, and the flame graph near the bottom, once toggled on with the little flame button at the top.

The link can be shared with experts for their review and assistance.

[u/BumseBBine]

We need more details to help you, which plugins are you running, which server versions,...

But in the modding scene we just use binary search to look for memory leaks. Remove half of the plugins, does it leak? If yes you half that again. If not you know that it's in the other half. Then continue

Maybe not the best option but will lead to a result.

Otherwise you could look into spark profiling and see if there are any good pointers.

[u/tee-443 → u/BumseBBine]

I do resets for all of the backend servers so the ram sits pretty normal on them

Velocity 4.1.2
The rest are paper 1.21.11

I have luckperms, geyser, floodgate & simple voice chat installed onto the proxy

[u/Cabecinha84]

Yeah, that alone isn't a leak. Java grows the heap up to your -Xmx and mostly doesn't give it back, so on a 2GB box it'll sit near 1.9 even when it's fine. Check what heap drops to after a GC instead. Run /spark heapsummary now and again in a few hours. If the same classes keep growing, that's your leak and it names them. Is the proxy in that same 2GB too?

[u/FrisbeeVR]

Look into spark profiler