# SFTPGo with PostgreSQL data provider and S3 backend
This tutorial shows the installation of SFTPGo on Ubuntu 20.04 (Focal Fossa) with PostgreSQL data provider and S3 backend. SFTPGo will run as an unprivileged (non-root) user. We assume that you want to serve a single S3 bucket and you want to assign different "virtual folders" of this bucket to different SFTPGo virtual users.
## Preliminary Note
Before proceeding further you need to have a basic minimal installation of Ubuntu 20.04.
## Install PostgreSQL
Before installing any packages on the Ubuntu system, update and upgrade all packages using the `apt` commands below.
```shell
sudo apt update
sudo apt upgrade
```
Install PostgreSQL with this `apt` command.
```shell
sudo apt -y install postgresql
```
Once installation is completed, start the PostgreSQL service and add it to the system boot.
```shell
sudo systemctl start postgresql
sudo systemctl enable postgresql
```
Next, check the PostgreSQL service using the following command.
PostgreSQL uses roles for user authentication and authorization, it just like Unix-Style permissions. By default, PostgreSQL creates a new user called `postgres` for basic authentication.
In this step, we will create a new PostgreSQL user for SFTPGo.
Login to the PostgreSQL shell using the command below.
```shell
sudo -i -u postgres psql
```
Next, create a new role `sftpgo` with the password `sftpgo_pg_pwd` using the following query.
```sql
create user "sftpgo" with encrypted password 'sftpgo_pg_pwd';
```
Next, create a new database `sftpgo.db` for the SFTPGo service using the following queries.
```sql
create database "sftpgo.db";
grant all privileges on database "sftpgo.db" to "sftpgo";
After installation SFTPGo should already be running with default configuration and configured to start automatically at boot, check its status using the following command.
We assume that you want to serve a single S3 bucket and you want to assign different "virtual folders" of this bucket to different SFTPGo virtual users. In this case is very convenient to configure a credential file so SFTPGo will automatically use it and you don't need to specify the same AWS credentials for each user.
The AWS CLI will create the credential file in `~/.aws/credentials`. The SFTPGo service runs using the `sftpgo` system user whose home directory is `/var/lib/sftpgo` so you need to copy the credentials file to the sftpgo home directory and assign it the proper permissions.
If you want to connect to PostgreSQL over a Unix Domain socket you have to set the value `/var/run/postgresql` for the `host` configuration key instead of `127.0.0.1`.
You can further customize your configuration adding custom actions and other hooks. A full explanation of all configuration parameters can be found [here](../full-configuration.md).
Next, initialize the data provider with the following command.
The default sftpgo systemd service will start after the network target, in this setup it is more appropriate to start it after the PostgreSQL service, so edit the service using the following command.
To start using SFTPGo you need to create an admin user, the easiest way is to use the built-in Web admin interface, so open the Web Admin URL and create the first admin user.
- Select `AWS S3 (Compatible)` as storage and then set `Bucket`, `Region` and optionally a `Key Prefix` if you want to restrict the user to a specific virtual folder in the bucket. The specified virtual folder does not need to be pre-created. You can leave `Access Key` and `Access Secret` empty since we defined global credentials for the `sftpgo` user and we use this system user to run the SFTPGo service.
You can mix S3 users with local users but please be aware that we are running the service as the unprivileged `sftpgo` system user so if you set storage as `local` for an SFTPGo virtual user then the home directory for this user must be owned by the `sftpgo` system user. If you don't specify an home directory the default will be `/srv/sftpgo/data/<username>` which should be appropriate.