Minecraft Elegance: Instant Obsidian Farm (32k/hr, Java 1.16.5, 1.17+)

IMPORTANT: The height of the snow golem in the boat was changed in 1.20.2+, so you need to adjust the build slightly:
https://imgur.com/a/0ZOp9nm
Note that a sticky piston is needed under the soul sand block.

A very simple obsidian farm that produces a stack of obsidian every 7 seconds. This farm may not work on modified servers, and changes to the design would be expected in order to make the farm work. See discussion below for more information.

IanXO4 discord server:   / discord  
WDL (Refer to 11:52): https://www.mediafire.com/file/ljxsii...

0:00 Intro
0:19 Material List, plus 1 stair
0:53 Mechanisms
5:34 Build Tutorial
11:52 Instructions for Use (IMPORTANT)
14:59 Outro
15:21 Manual mining

NOTES:
2:12 The farm can also work with a snow golem as the target at the player station, but it requires that the snow golem in the stronghold to face in the opposite direction so that the wither doesn't come under attack from 2 mobs, which would trigger blue skulls. This configuration has slower rates because many of the snowballs will miss.
5:46 If you play on a modified server, you may have better luck with a different chunk loader design:    • 1.19 Chunk Loader  
   • Simple Paper-friendly Chunk Loader | ...  
To make Dark's chunk loader on SPIGOT, you may need a second hopper minecart and hopper under the base of the portal to collect the boat.
7:15 Silverfish can become trapped in boats, which prevents despawning, but they can also infest blocks while inside of a boat.
7:30 If you've already destroyed all infested stone blocks, you can use a nametagged endermite instead of a silverfish. Repeatedly throw enderpearls until you get an endermite, and make sure that you nametag it before trapping it in a boat.
8:11 Make sure you attach the redstone torch to the block under the pressure plate.
11:08 A pool of water around the player will also work, but I don't use this approach because it carries a risk that if the water stream from the bubble column merges with the pool for any reason, you will not be able to remove the flowing water, and this will prevent the iron golem from reaching the wither.
11:52 You might want to bring a bucket of milk, too, in case something goes wrong. An easy way to kill a loose wither is to lure it over the void, and then quickly fly away so that it sinks into the void.
12:03 There are reports that a punch bow can knock the wither out of the trap.
12:21 Some modified servers allow items to group together at long distances, so you may need 2 different types of junk items to get the despawn timer started. Be mindful that the wither may behave differently on modified servers.
14:52 If you need to stop the farm early in single player, just quit and restart the game to unload the stronghold. Shoot the wither again with an arrow and then build the iron golem. On a multiplayer server, you can have a friend lower the snow golem out of the portal in the stronghold to make it safe for an iron golem to kill the wither.

PAPER SERVERS
At 11:25, expand the soul sand and water sources horizontally to a 3x3 array. You may need a second player instead of a chunk loader in the stronghold. This player can operate the piston with a lever so that you don't need a despawn timer. Otherwise, see the note above at 12:21. The wither behaves a little differently on Paper, so the farm is slightly more dangerous.

REFERENCES:
Rooftop Joe's chunk loader:    • Compact Perma Loader (Minecraft 1.15+)  
Dark's chunk loader:    • The Simplest Portal Chunkloader  
Wither trap: https://www.bilibili.com/video/BV1cZ4...
Scorpio's channel:    / scorpio03  
Wither Archive discord server:   / discord  
Mojang statement about mobs spawning in portals for future updates: https://www.minecraft.net/en-us/artic...