On fait un snapshot de la base sur Babar

/usr/local/pgsql/bin/psql -U postgres -h 127.0.0.1 -p 5433 -c "select pg_start_backup('init dumbo')"
sudo cp -pr /data/postgresql-9.0 /data/postgresql-9.0-export-dumbo
/usr/local/pgsql/bin/psql -U postgres -h 127.0.0.1 -p 5433 -c "select pg_stop_backup()"

Préparation et export du snapshot sur Babar

sudo su - postgres
cd /data/postgresql-9.0-export-dumbo
rm postmaster.pid
rm pg_xlog/*
echo 'hot_standby = on' >> postgresql.conf
echo "standby_mode = 'on'" >> recovery.conf
echo "restore_command = 'cp -i /var/lib/postgresql/babar_wals/%f %p'" >> recovery.conf
echo "primary_conninfo      = 'host=212.85.154.68 port=5433 user=postgres'" >> recovery.conf
echo "trigger_file = '/var/lib/postgresql/9.0/failover.trigger'" >> recovery.conf
scp -pr /data/postgresql-9.0-export-dumbo/* dumbo.postgresql.fr:/data/postgresql-9.0-export-dumbo/

Sur dumbo, on charge le snapshot et on démarre en mode recovery/standby

sudo /etc/init.d/postgresql-9.0 stop
sudo mv /data/postgresql-9.0 /data/postgresql-9.0-orig
sudo mv /data/postgresql-9.0-export-dumbo /data/postgresql-9.0
sudo chmod 700 -R /data/postgresql-9.0
sudo /etc/init.d/postgresql-9.0 start

Il ne reste plus qu'à tester sur Dumbo :

/usr/local/pgsql/bin/psql  -h 127.0.0.1 -p 5433 -c "SELECT pg_is_in_recovery();";
 pg_is_in_recovery 
-------------------
 t
(1 row)