MySQL

MySQL 8 or newer. MariaDB works through the same dialect.

Create the database

CREATE DATABASE uxmclaims CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
CREATE USER 'uxmclaims'@'localhost' IDENTIFIED BY 'a-long-random-password';
GRANT ALL PRIVILEGES ON uxmclaims.* TO 'uxmclaims'@'localhost';
FLUSH PRIVILEGES;

utf8mb4 matters: claim names contain emoji more often than you would expect, and utf8 in MySQL is a three-byte encoding that cannot store them.

Use 'uxmclaims'@'%' instead of @'localhost' when the database is on another host, and restrict it at the firewall rather than trusting the wildcard.

Point the plugin at it

database:
  type: 'AUTO'
  username: 'uxmclaims'
  password: 'a-long-random-password'
  url: 'jdbc:mysql://localhost:3306/uxmclaims'

AUTO reads mysql out of the URL. Restart the server: this section is not re-read by /claim reload.

Useful URL parameters:

jdbc:mysql://localhost:3306/uxmclaims?useSSL=false&characterEncoding=utf8&serverTimezone=UTC

Set serverTimezone when the database host and the game server disagree about time. Claim expiry is stored as an instant, but a mismatched session timezone makes every date: placeholder read wrong.

Several servers

More than one server may share one database. That is the main reason to be here.

What is shared: claims, members, roles, warps, bans, vaults. What is not: the in-memory caches. A claim edited on one server is not instantly visible on another: there is no cross-server invalidation message. Give each server its own worlds, and the question does not arise.

Backups

mysqldump -u uxmclaims -p uxmclaims > uxmclaims-$(date +%F).sql

Run it before any bulk operation. /claim admin bulk rename has no undo and no confirmation.