# Database
URL: https://usememos.com/docs/configuration/database

Memos supports three database backends:

* `sqlite` for the default single-instance setup
* `mysql` for managed or larger deployments
* `postgres` for managed or larger deployments

## SQLite [#sqlite]

SQLite is the default and the best fit for most personal deployments or small teams running a single node.

Useful defaults in Memos include WAL mode and a busy timeout, which help reduce common lock contention problems.

Typical SQLite setup:

```bash
MEMOS_DRIVER=sqlite MEMOS_DATA=/var/opt/memos memos
```

If you need an explicit file path:

```bash
MEMOS_DRIVER=sqlite MEMOS_DSN=/opt/memos/memos.db memos
```

SQLite is usually enough when:

* one instance handles all writes
* your dataset is modest
* operational simplicity matters more than cluster-style scaling

## MySQL and PostgreSQL [#mysql-and-postgresql]

Use MySQL or PostgreSQL when:

* you want managed backups and tooling
* you already operate a database server
* you expect larger datasets or more operational controls
* you do not want the application host to carry the database file locally

Examples:

```bash
MEMOS_DRIVER=mysql \
MEMOS_DSN="memos_user:password@tcp(db:3306)/memos?charset=utf8mb4&parseTime=True&loc=Local" \
memos
```

```bash
MEMOS_DRIVER=postgres \
MEMOS_DSN="postgres://memos_user:password@db:5432/memos?sslmode=disable" \
memos
```

## Selection guidance [#selection-guidance]

* choose SQLite for one-node simplicity
* choose MySQL or PostgreSQL for operational flexibility
* keep backups aligned with your database choice
* if you store attachments outside the database, back those up separately

## Performance implications [#performance-implications]

Database choice changes where bottlenecks show up:

* SQLite tends to surface write contention first
* MySQL and PostgreSQL push complexity into networked DB operations and tuning
* attachment storage can dominate recovery and backup time even when the DB is healthy