matrix-docker-ansible-deploy/docs/maintenance-migrating.md

> **Note**: This migration guide is applicable if you migrate from one server to another server having the same CPU architecture (e.g. both servers being `amd64`). 
> 
> If you're trying to migrate between different architectures (e.g. `amd64` --> `arm64`), simply copying the complete `/matrix` directory is not possible as it would move the raw PostgreSQL data between different architectures. In this specific case, you can use the guide below as a reference, but you would also need to dump the database on your current server and import it properly on the new server. See our [Backing up PostgreSQL](maintenance-postgres.md#backing-up-postgresql) docs for help with PostgreSQL backup/restore.

# Migrating to new server

1. Prepare by lowering DNS TTL for your domains (`matrix.DOMAIN`, etc.), so that DNS record changes (step 4 below) would happen faster, leading to less downtime
2. Stop all services on the old server and make sure they won't be starting again. Execute this on the old server: `systemctl disable --now matrix*`
3. Copy directory `/matrix` from the old server to the new server. Make sure to preserve ownership and permissions (use `cp -p` or `rsync -ar`)!
4. Make sure your DNS records are adjusted to point to the new server's IP address
5. Remove old server from the `inventory/hosts` file and add new server.
6. Run `ansible-playbook -i inventory/hosts setup.yml --tags=setup-system-user`. This will create the `matrix` user and group on the new server
7. Because the `matrix` user and group are created dynamically on each server, the user/group id may differ between the old and new server. We suggest that you adjust ownership of `/matrix` files manually by running this on the new server: `chown -R matrix:matrix /matrix`.
8. Run `ansible-playbook -i inventory/hosts setup.yml --tags=setup-all,start` to finish the installation and start all services