TSWoW supports managing multiple realms from a single installation, and additionally managing separate sets of module data that should be applied for each realm.
Since version 0.13, realms and datasets are stored in the special module endpoints datasets and realms.
A realm manages its own character database, worldserver.conf and a worldserver process, but shares account information with the entire TSWoW installation.
Realms are configured to one and only one dataset, which defines what world database is used and what client versions can connect to it.
Realms can be created simply by creating a folder realms/my-new-realm to a module.
Realms are referenced by the full name of their parent module followed by a dot and the realm name. For example, the realm my-realm inside the module my-module has the full name my-module.my-realm.
Please note that it is not permitted to have realms, datasets or submodules sharing the same full name.
A dataset manages a full set of modules and the data used to build them. Datasets allow tswow developers to maintain multiple discrete sets of gamedata from a single installation. Different datasets can be built with different input dbc data, and filter out different modules from a build.
Since datasets builds completely different client and server files, each dataset manages its own world database and server files, such as dbc, luaxml, maps/vmaps/mmaps and ids.
Datasets can be created simply by creating a folder datasets/my-new-dataset to a module.
Datasets are referenced by the full name of their parent module followed by a dot and the dataset name. For example, the dataset my-dataset inside the module my-module has the full name my-module.my-dataset.
Datasets can be specifically targeted with build commands simply by including its full name: build data my-module.my-dataset.
An alternative name suggested for datasets during development was expansions. We ultimately rejected this to not give users the idea that tswow supported multiple blizzard expansions (which we don’t), but the reasoning behind it might be helpful for some users to understand the purpose of datasets. Datasets allow you to effectively manage multiple custom expansions to the base game from a single installation, since they can build completely different data for different realms depending on what modules or submodules they build.
TSWoW includes a default dataset and realm inside the default module to make development easier for new users. When using commands such as build data or start realm, tswow will automatically select this dataset and this realm unless another name is specified.
You can change the default dataset that tswow selects in node.conf (inside the root directory of your tswow installation) by changing the fields Default.Realm and Default.Dataset. This is recommended if you wish to bundle your own datasets and realms in your modules.