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docs/installation/4_database.md

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+---
+title: Preparing database storage
+parent: Installation
+nav_order: 3
+permalink: /installation/database
+---
+
+# Preparing database storage
+
+Dendrite uses SQL databases to store data. Depending on the database engine being used, you
+may need to perform some manual steps outlined below.
+
+## SQLite
+
+SQLite deployments do not require manual database creation. Simply configure the database
+filenames in the Dendrite configuration file and start Dendrite. The databases will be created
+and populated automatically.
+
+Note that Dendrite **cannot share a single SQLite database across multiple components**. Each
+component must be configured with its own SQLite database filename. You will have to remove
+the `global.database` section from your Dendrite config and add it to each individual section
+instead in order to use SQLite.
+
+### Connection strings
+
+Connection strings for SQLite databases take the following forms:
+
+* Current working directory path: `file:dendrite_component.db`
+* Full specified path: `file:///path/to/dendrite_component.db`
+
+## PostgreSQL
+
+Dendrite can automatically populate the database with the relevant tables and indexes, but
+it is not capable of creating the databases themselves. You will need to create the databases
+manually.
+
+At this point, you can choose to either use a single database for all Dendrite components,
+or you can run each component with its own separate database:
+
+* **Single database**: You will need to create a single PostgreSQL database. Monolith deployments
+  can use a single global connection pool, which makes updating the configuration file much easier.
+  Only one database connection string to manage and likely simpler to back up the database. All
+  components will be sharing the same database resources (CPU, RAM, storage).
+
+* **Separate databases**: You will need to create a separate PostgreSQL database for each
+  component. You will need to configure each component that has storage in the Dendrite
+  configuration file with its own connection parameters. Allows running a different database engine
+  for each component on a different machine if needs be, each with their own CPU, RAM and storage —
+  almost certainly overkill unless you are running a very large Dendrite deployment.
+
+For either configuration, you will want to:
+
+1. Configure a role (with a username and password) which Dendrite can use to connect to the
+   database;
+2. Create the database(s) themselves, ensuring that the Dendrite role has privileges over them.
+   As Dendrite will create and manage the database tables, indexes and sequences by itself, the
+   Dendrite role must have suitable privileges over the database.
+
+### Connection strings
+
+The format of connection strings for PostgreSQL databases is described in the [PostgreSQL libpq manual](https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-CONNSTRING). Note that Dendrite only
+supports the "Connection URIs" format and **will not** work with the "Keyword/Value Connection
+string" format.
+
+Example supported connection strings take the format:
+
+* `postgresql://user:pass@hostname/database?options=...`
+* `postgres://user:pass@hostname/database?options=...`
+
+If you need to disable SSL/TLS on the database connection, you may need to append `?sslmode=disable` to the end of the connection string.
+
+### Role creation
+
+Create a role which Dendrite can use to connect to the database, choosing a new password when
+prompted. On macOS, you may need to omit the `sudo -u postgres` from the below instructions.
+
+```bash
+sudo -u postgres createuser -P dendrite
+```
+
+### Single database creation
+
+Create the database itself, using the `dendrite` role from above:
+
+```bash
+sudo -u postgres createdb -O dendrite dendrite
+```
+
+### Multiple database creation
+
+The following eight components require a database. In this example they will be named:
+
+| Appservice API | `dendrite_appservice`    |
+| Federation API | `dendrite_federationapi` |
+| Media API      | `dendrite_mediaapi`      |
+| MSCs           | `dendrite_mscs`          |
+| Roomserver     | `dendrite_roomserver`    |
+| Sync API       | `dendrite_syncapi`       |
+| Key server     | `dendrite_keyserver`     |
+| User API       | `dendrite_userapi`       |
+
+... therefore you will need to create eight different databases:
+
+```bash
+for i in appservice federationapi mediaapi mscs roomserver syncapi keyserver userapi; do
+    sudo -u postgres createdb -O dendrite dendrite_$i
+done
+```