The Killd Board / Axolotls
How many axolotls does it take to crash a Minecraft server?
2,906, which puts an axolotl within a couple of hundred of a villager and ahead of every other passive mob we have tested. That surprised us, because an axolotl looks like the least threatening thing we spawned. It died at 10,357.
Paper 1.21.11 · AMD Ryzen 7 9700X · 6GB allocated
Why axolotls cost so much
Water mobs navigate in three dimensions. A land mob solves a path across a mostly flat grid; a swimming mob searches a volume, and the search space grows fast. Axolotls also hunt, play dead, track a target and follow players holding a bucket, so the behaviour list is longer than the animal suggests. Cute is not cheap.
How we tested it
Everything spawned into a single chunk, in one pile, with the server left running until the tick rate gave up. The server ran Paper 1.21.11 on an AMD Ryzen 7 9700X with 6GB allocated, which is the same hardware and the same RAM policy as an ordinary Hostd plan. We watched TPS and tick times rather than guessing, wrote down the count where the server first fell behind, and kept spawning until it either died or made it clear it was not going to.
The general lesson is that pathfinding cost scales with the space a mob can move through. Anything that swims or flies is worth more of your attention than the same number of cows.
What this means for your server
If your own server is printing Can't keep up! Is the server overloaded? the cause is the same shape as this one: something in the tick loop is taking longer than its 50ms budget. Roastd reads your RAM allocation, view distance, player slots, JVM flags and logs and names which of those it is. No account, no world upload, no charge.
Questions about axolotls
Do axolotls lag a Minecraft server?
In normal numbers, no. In an axolotl farm, yes, and more than you would expect: it took only 2,906 in one chunk to drag our test server below 20 TPS. Water pathfinding searches a three-dimensional volume rather than a surface, which is what makes them expensive per mob.
Are water mobs worse for server performance than land mobs?
Generally yes, per mob. Swimming navigation searches in three dimensions, so the pathfinding work is larger than the equivalent land mob. That is why a big fish or axolotl farm can cost more tick time than a much bigger pen of cows.
Elsewhere on the board
Keep reading
Rent the machine we keep breaking
Same AMD Ryzen 7 9700X, same hard-reserved RAM, same NVMe. Yours will not have 10,357 axolotls in one chunk, which gives it a considerable head start. Online in under a minute, with a free address, DDoS protection and a 7-day money-back guarantee.