When an instance has the
barman role in
configures the instance as a Barman server to take backups
of any other instances that name it in their
postgres instances can have the same Barman server named as
postgres instance can have a list of
Barman servers named as its
backup. In this case, backups are taken to all
of the named servers.
The default Barman configuration connects to PostgreSQL using
pg_receivewal to take continuous backups of WAL. It takes a full
backup of the instance using rsync over ssh twice weekly. Full backups
and WAL are retained for long enough to enable recovery to any point in
the previous 4 weeks.
On each Barman server, a global configuration file is created
/etc/barman.conf. This file contains default values for many Barman
configuration variables. For each Postgres server being backed up,
an additional Barman configuration file is created. For example, to back up the
one, the file is
/etc/barman.d/one.conf, and the backups
are stored in
/var/lib/barman/one. The file and directory names
are taken from the backed-up instance's
backup_name setting. The default for this setting
is the instance name.
You can set the following variables on the backed-up instance. They are
passed through into Barman's configuration with the prefix
|RECOVERY WINDOW OF 4 WEEKS
TPA installs a cron job in
/etc/cron.d/barman that runs every
minute and invokes
barman cron to perform maintenance tasks.
For each instance being backed up, TPA installs another cron job in
/etc/cron.d/<backup_name> that takes the backups of that instance.
This job runs as determined by the
barman_backup_interval variable for
the instance. The default is to take backups at 04:00 every
Wednesday and Saturday.
TPA generates ssh key pairs for the postgres and barman
users and installs them into the respective
~/.ssh directories. Keys for
the postgres user are added to the barman
authorized_keys file, and
keys for the barman user are added to the postgres
The postgres user must be
able to ssh to the Barman server to archive WAL segments (if
configured), and the barman user must be able to ssh to the Postgres
instance to take or restore backups.