POSTGRES REPLICATION

Postgres.txt

# Viewing your Posgtres Clusters

sudo pg_lsclusters 

# create a second postgres cluster 
sudo pg_createcluster 10 replica1 

#checking the status of the cluster
sudo pg_ctlcluster 10 replica1 status 
sudo systemctl status postgresql@10-main 

# create archive directories for both clusters 
This is where the wal keep segments are stored
sudo -H -u postgres mkdir /var/lib/postgresql/pg_log_archive/main 
sudo -H -u postgres mkdir /var/lib/postgresql/pg_log_archive/replica1 


## Configure Main Cluster (Primary / Master) ################################################### 

# edit configuration file 
sudo nano /etc/postgresql/10/main/postgresql.conf 

# edit host based access file 
sudo nano /etc/postgresql/10/main/pg_hba.conf 
This enables your server to accept connections with the replica
This should be set more securely in production

# create replication user 
sudo -H -u postgres psql -c "CREATE USER rep_user WITH replication;" 


# restart the main cluster 
sudo systemctl restart postgresql@10-main