Forum: gaming.stackexchange.com
Tags: <minecraft-java-edition><minecraft-java-edition-server>
Title: How can I prevent a world from getting too large without installing plug-ins?
Question: I was hoping to have a pure vanilla server, but the size of the world is causing huge memory usage when only a few players are on the server. Is there a way I can prevent users from exploring so far in the vanilla version of Minecraft?

Answers:
sents: text: This isn't a mod, but it will help with your issue.
text: I have used this method on my server, and it helped cut down on A LOT of lag.
text: Download
text: MCEdit, a world-editing tool, from their website ( http://www.mcedit.net ).
text: Inside of MCEdit, chose which world you would like to create the border on.
text: Make walls around the area you wish to have players kept in, using the invisible Block 36.
text: This method above will keep everyone within the walls of Block 36, allowing no new chunks to form, so your game runs faster!
text: Hope this helps!
answer_details: author: gaming.stackexchange.com/users/63122/Andrew
score: 7
sents: text: Not to my knowledge.
text: The only mods that are still up to date with Minecraft are Bukkit plugins only.
text: Also, while it is possible for large worlds to cause memory usage issues, it's not the most common of issues.
text: I'm sure you've already done your research, but you may want to verify that it is in-fact, a world size issue.
answer_details: author: gaming.stackexchange.com/users/50823/Linuxmint
score: 6
sents: text: Yes, you can, and you can do it without any mods or external editors, and without generating all of the terrain you want to section off.
text: You can do this by setting up a simple redstone clock circuit connected to one or more command blocks .
text: If, for example, you wanted to limit players to within 2500 blocks of 0,0, you could then use the player selector @a[x=0,y=64,z=0,rm=2500] to select all players "out-of-bounds".
text: Just make sure that this setup is encased in bedrock or inaccessible from non-op players.
text: Using this, you could do things like tell them to turn around using /tell , teleport them back to spawn using /tp or /kill them outright, or anything else you want such as progressively slowing them down with /effect as they wander off.
answer_details: author: gaming.stackexchange.com/users/9350/dlras2
score: 5
sents: text: As anyone hasn't said anything about the reasons behind exploring, I thought I could share some experience (although this might be dated).
text: Maps more often than not concentrate a very large featureless biome (desert or tundra) on the start point.
text: As Minecraft concentrates certain resources (such as sugar cane, or snow, or even wood) on certain biomes, the key to having a good map would be to get a seed that somehow concentrates any desirable feature around 640 to 1152 blocks of the center point (as all strongholds are located at random positions in that radius).
text: Then, as suggested by @Tech, you can wall off the exterior sections.
text: I must tell you that it is impossible to completely cut off a section of a map.
text: Minecraft was made to be an endless experience.
text: Walling the "real world" doesn't wall off the Nether.
text: Assuming you could wall off the Nether, people could, with some effort, climb the walls.
text: I have sporadically used some mods but they failed more often than they should.
text: The best course of action, all considered, is to ask gently not to explore much.
text: And the best way to prevent that is by limiting the urge to explore.
answer_details: author: gaming.stackexchange.com/users/54659/Doktoro Reichard
score: 1
sents: text: I had a similar issue.
text: I bought a $10 a month hosting plan from DigitalOcean, and needed it to not use up the 1 gig of memory I had, as I needed to run some other servers.
text: Simply use world border!
text: If you have a 1.8 server, you can use /worldborder
text: set number of blocks to set the maximum number of blocks players can go from the world spawn point.
text: You can set that too with /setworldspawn.
text: You can read more about these commands at http://minecraft.gamepedia.com/Commands#worldborder and http://minecraft.gamepedia.com/Commands#setworldspawn
text: You can also disable the Nether in server.properties if you wish!
answer_details: author: gaming.stackexchange.com/users/138538/atoms118
score: 1

Summary of the answers:
Try limiting the urge to explore.
While it is nearly impossible to limit a Minecraft world, without mods, it seems that the user can take some actions that might work, such as using commands.