Backup with ``rsync`` /SSH
--------------------------

The backup over ``rsync`` was the only method for backups in Barman
before version 2.0, and before 3.11 it was the only method that
supported incremental backups. Current Barman supports file-level as
well as block-level incremental backups. Backups using ``rsync``
implements the file-level backup feature. Please consult the *“Features
in detail”* section for more information.

To take a backup using ``rsync`` you need to put these parameters inside
the Barman server configuration file:

.. code:: ini

   backup_method = rsync
   ssh_command = ssh postgres@pg

The ``backup_method`` option activates the ``rsync`` backup method, and
the ``ssh_command`` option is needed to correctly create an SSH
connection from the Barman server to the PostgreSQL server.

..  IMPORTANT ::
   You will not be able to start a backup if WAL is not being correctly archived to Barman, either through the `archiver`  or the `streaming_archiver` 

To check if the server configuration is valid you can use the
``barman check`` command:

.. code:: bash

   barman@backup$ barman check pg

To take a backup use the ``barman backup`` command:

.. code:: bash

   barman@backup$ barman backup pg

..  NOTE::
   Starting with Barman 3.11.0, Barman uses a keep-alive mechanism when taking rsync-based backups. It keeps sending a simple `SELECT 1`  query over the libpq connection where Barman runs `pg_backup_start` /`pg_backup_stop`  low-level API functions, and it's in place to reduce the probability of a firewall or a router dropping that connection as it can be idle for a long time while the base backup is being copied. You can control the interval of the hearbeats, or even disable the mechanism, through the `keepalive_interval`  configuration option.