I'm hitting my head against the wall here. I'm running a vanilla Minecraft server (1.9) on a VPS server. Right now, it has 6gb of RAM allocated to it, and it's being run with Multicraft. When watching the RAM usage, it seems to be quickly climbing to 50% of the allocated RAM and then over the course of an hour it eventually climbs to 100%. It seems to be caching something, but I'm not sure what or how to fix it, and I believe the shortage of ram is what causes the block lag after it's been running for a bit (there's a direct correlation between the RAM usage and the block lag).

At the moment, I have a pretty bare bones setup with the command blocks, and I've tried re-working the command room a few times to help reduce the load on the server. I've tried disabling anything that isn't completely necessary for players (turning off a lot of the staff functionality) to see if it would help and it hasn't made any difference either way, which leads me to believe that it's not my command setup.

For the 1.8 server I had before 1.9 was released, I had mini-games, etc, on top of the basic command blocks and I was able to run the server without any issues with 4gb of ram and 5-15 players online at a time. I'd like to avoid adding a ridiculous amount of RAM as a workaround, as VPS RAM is really expensive.

As a work-around, I have the server restarting hourly to clear out whatever's being cached, but when there are a lot of players online, it's still a problem.

Does anyone have any idea what's going on? Is it 1.9 itself, or is it something that I should check out server-side that I'm not thinking of? Any configuration ideas that I could try? I'm at a complete loss.

  • Try downgrading to 1.8 if the server supports it??? I don't know Commented Mar 23, 2016 at 23:55
  • How large is the world?
    – Sulphate
    Commented Mar 24, 2016 at 18:24
  • @Sulphate The last backup (from yesterday) was a 2.5 GB zip file, and size wise is 45,000 x -45,000
    – theBeaks
    Commented Mar 25, 2016 at 6:03
  • Yeah xD worlds that large can cause insane amounts of lag due to the huge number of chunks that have to be loaded.
    – Sulphate
    Commented Mar 25, 2016 at 17:55
  • @Sulphate The 1.8.x server that I was running had the same world border, and the backups were about 9 GB all zipped up, plus I had mini-games, etc running on top of all the basic stuff and I was able to run that without lag with 4GB of RAM, so I don't think that's it
    – theBeaks
    Commented Mar 26, 2016 at 0:56

2 Answers 2


Last time I was having issue with ram steadily rising and not falling, it was a Java issues. Java was not performing garbage collection correctly. I fixed it by reinstalling Java and it worked fine!


There is one short answer: Or buy a super-ultra-mega-epic computer/server or downgrade to 1.8. Faster internet connection may also help.
Many people are having simmilar problem with their 1.9 servers. This block lags are most probably NOT caused by Command blocks, but by 1.9 new chunk generation. It takes more time and calculation to make a new chunk, load blocks and/or change block values, update things, spawn and "render" new entities (especially Armor stands) and also check and control the new Minecraft 1.9 security features.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .