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Changing PostgreSQL's default data directory


This post is supposed to be a small guide to changing PostgreSQL's data directory whether your system already contains a PostgreSQL cluster or not, runs SystemD or SELinux is enforced.

Defining the new path

The PostgreSQL server loads it's data path from an enviroment variable when starting.

If your distribution uses SystemD as it's init system, you can safely modify the enviroment of PostgreSQL with this command.

systemctl disable postgresql.service
systemctl edit --full postgresql.service

Edit the line containing Environment=PGDATA= to something like this.

Environment=PGDATA=/mnt/storage/postgresql/data

If you mess up PostgreSQL's service file, delete /etc/systemd/system/postgresql.service and run systemctl daemon-reload. This will revert back to the default service file provided by your package manager. Then repeat the steps above.

Permissions

The PostgreSQL user needs access to the directory containing the cluster data.

chown -R postgres:postgres /mnt/storage/postgresql

SELinux

If you run Fedora Server or another distribution implementing SELinux, the PostgreSQL SystemD service needs access to your new data directory.

You can just “copy” all SELinux configurations from the default PostgreSQL directory to your new path.

semanage fcontext -a -e /var/lib/pgsql /mnt/storage/postgresql
restorecon -RF /mnt/storage/postgresql

PostgreSQL

If you already have a PostgreSQL cluster, copy it's data to your new directory.

rsync -av /var/lib/pgsql/data /mnt/storage/postgresql

New database cluster

If you don't have an existing PostgreSQL database cluster, you also need to modify /etc/postgresql-setup/upgrade/postgresql.conf.

Then continue with initializing a PostgreSQL cluster.

Done!

That's it! You can now enable and start your PostgreSQL server.

systemctl enable --now postgresql.service

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