Minecraft – Why are the creepers not spawning

I was able to talk about my problem to the Creator of the linked Video above myself via Teamspeak.

Here are some things to keep in mind when building a huge farm like that:

• You absolutely need to clear out a HUGE perimeter around the farm to make sure mobs can only spawn in the area you want them to spawn.
• The perimeter around the farm needs to be 128x128. In my case i only cleared out like 50x50 which is by far not enough and the main reason i got extremly low spawn rates compared to JL's video.
• In MC 1.7 and before it is extremly important to notice that the LC Value (as seen in the debug screen) has a huge impact on the farm and spawning behaviour. The LC Value saves for the given chunk how huge the player has builded in this chunk ever since creation of the chunk. For example you go in newly generated terrain at Y = 50 the LC Value will be 50. If you build a 10 high tower on that place the LC will go up to 60. Note that to have good spawning behaviour your LC value needs to be as low as possible.
• Explanation why the LC Value needs to be as low as possible: When MC trys to spawn a Mob in a given chunk, it only will try to spawn it in the area of the chunk under the LC Value. So, if there are several chunks around your farm with a high LC Value, the higher the chance is, that mobs outside of your farm will spawn, because the given chunk actually has more blocks to spawn mobs upon.
• There also is a mobcap on each MC server. So, if you are alone on the server the complete Mobcap will only be taken by you. If there are more players on the server and they even are in different regions, than statistically each player would get halve of the mobcap which means getting halve of the mobspawns.
• There also is a possibility that mobs will be spawned at the edge of the 128x128 perimeter and not despawn instantly due to a bug / feature. JL told me that when a mob is spawned directly at the edge of the 128x128 perimeter and it touches the end of the render distance the game will put this mob into a "sleep" mode thus stopping rendering it. This however causes the mob to still count to the server mobcap while not despawning. Which means it lowers your spawn rate.

This are the reasons i remember, actually JL has told me far more. I convinced him to post a video on that topic on youtube and explane the topic far more in details. The video will come soon from him.

Hope this helps somebody.

The first thing to remember is that Spigot's entire reason for existence is to increase the normal server performance. With this being the main intent server managers would have when installing Spigot the default settings are set to a base "improved" performance level.

To bring your server back to "vanilla like" mob spawning you need to adjust two files.

1. In your Spigot.yml file (in your server root directory) you should check to ensure that the mob-spawn-range is set to 4 (chunks).

   mob-spawn-range: 4

   You can disable experience orb and item grouping by setting the merge-radius to zero.

   merge-radius: exp: 0 item: 0

   At the bottom of thsi file you can adjust most of these settings on a per world basis. If you want all worlds to use the same setting you can just remove the entire separate world groupings and just leave the default grouping.

2. In your Bukkit.yml file (in your server root directory) you need to ensure that the spawn-limits for each type are set as follows:

   spawn-limits: monsters: 70 animals: 10 ambient: 15 water-animals: 5

   Also within this file you will want to check your ticks-per setting to make sure it is set to 1 for hostiles and 400 for animals (all others).

   ticks-per: animal-spawns: 400 monster-spawns: 1