FTB Revelation 2.7.0 -- Memory Issues

[Whisker]

Hey friends!

I've been battling memory leak-related issues ever since I set up my server, and I haven't been able to resolve the issue in any capacity . I originally posted on the SpongeForums about this issue, but I figured I should also head over here as I have unfortunately not heard a peep from then on potential solutions. This has grown to be a long thread, so I appreciate anyone for reading through it all and offering their thoughts!

Server Info
RAM: 5gb
FTB Revelation 2.7.0
Minecraft 1.12.2
Forge
SpongeForge

Other plugins used:
MagiBridge
MBDiscordLink
RandomPatches
GriefPrevention
LuckPerms
Nucleus

I’m currently running into what I believe to be a memory leak with my FTB Revelation server. About every three hours, my server is automatically restarted due to it exceeding 5.5gb of ram usage.

Here’s a graph of the memory and CPU usage:


(on the 5th of February, I upgraded the server from 4gb to 5gb, hence the increase)

I’ve been trying to diagnose as best as I can, but Minecraft servers are not my area of expertise by any means. I’ve also been trying to gather info from timings and heap dumps, but timing reports seem to indicate no issues (to the untrained eye, maybe?) and I can’t quite figure out how to interpret heap dumps-- help in this area would be greatly appreciated.

I’ve removed a few plugins (Prism, spark) entirely and temporarily disabled MagiBridge and MBDiscordLink to attempt to resolve the issue but haven’t had luck.

These issues have been happening prior to any major “advancements” in the modpack, so to speak (use of higher end technology mods, etc). When there are no players on the server, the ram climb slows down but is still present. This can be seen in the overnight areas of this graph:



-- (everything prior to this was on FTB Revelation 2.6.0) --

I’ve now tried this to no avail: generating a new world with the current modpack (with no additional mods and with added mods [SpongeForge, Nucleus, LuckPerms, GriefPrevention, MagiBridge]). Resulted in the same issue. Here’s the usage:

The first three peaks are a new world on a new install of FTB Revelation 2.6.0 with no other mods. The last peak is with the additional mods listed above.

Misc info:
- I’ve tried to use Eclipse Memory Analyzer with heap dumps generated form Sponge, but I don’t think I’m doing it right hahaha. If anyone has a guide (or would be willing to look at a heap dump) let me know!
- After 13 minutes of the server being up it produced a heap dump 1.7gb in size. Is this normal?

----

Sorry for the info dump, but I'm not super in the know when it comes to the nitty gritty of troubleshooting server issues, so I figured the best approach would be to include as much info as possible. Thank you!

[hiimcody1]

I am not familiar with that specific pack, however a big source of leaks can be chunk loading and mods that use their own threads.

Do you have any kind of computer mods, such as computercraft or opencomputers?

Also, are you using multiple worlds (even if it is something like rftools dimensions or mystcraft)?

[Whisker]

There are chunk loaders and other dimensions, yeah. Chunk loaders didn't come into play until after the whole memory leak issue was discovered, and the other dimensions weren't too utilized until later on as well.

The Twilight Forest is known to be a huge leak source, and the server definitely auto restarts much quicker when someone is icnthere. As far as the other dimensions go, though, they dont seem to affect the general memory usage climb too much.

I'm still confused as to what's going on given that even a new world didn't fix solve the issues

[hiimcody1]

If memory is spiking even with a new world, that points towards a mod going haywire.

When you are able, please open a support request and ask to be assigned to Cody. I'd like to take a look at your server and try some startup line changes to see if we can get those restarts under control by lowering the allocated ram amount a bit, and possibly messing with your permgen/metaspace.