Fix PostgreSQL 16 paths in pgbackrest.md (#509)

In this commit, I've corrected the PostgreSQL paths in the configuration file from '/var/lib/postgresql/11' to '/var/lib/postgresql/16/main'. The previous paths were pointing to an incorrect version (11), and the corrected paths now accurately reflect the PostgreSQL 16 installation directory.

This change ensures that the configuration aligns with the actual installation location, preventing potential issues and improving clarity for users or administrators managing the PostgreSQL instance.

docs/solutions/pgbackrest.md

@@ -100,7 +100,7 @@ You also need a backup storage to store the backups. It can either be a remote s
     pg1-host=${NODE1_NAME}
     pg1-host-port=8432
     pg1-port=5432
-    pg1-path=/var/lib/postgresql/11/
+    pg1-path=/var/lib/postgresql/16/main
     pg1-host-type=tls
     pg1-host-cert-file=/pg_ha/certs/${SRV_NAME}.crt
     pg1-host-key-file=/pg_ha/certs/${SRV_NAME}.key
@@ -111,7 +111,7 @@ You also need a backup storage to store the backups. It can either be a remote s
     pg2-host=${NODE2_NAME}
     pg2-host-port=8432
     pg2-port=5432
-    pg2-path=/var/lib/postgresql/11/
+    pg2-path=/var/lib/postgresql/16/main
     pg2-host-type=tls
     pg2-host-cert-file=/pg_ha/certs/${SRV_NAME}.crt
     pg2-host-key-file=/pg_ha/certs/${SRV_NAME}.key
@@ -121,7 +121,7 @@ You also need a backup storage to store the backups. It can either be a remote s
     pg3-host=${NODE3_NAME}
     pg3-host-port=8432
     pg3-port=5432
-    pg3-path=/var/lib/postgresql/11/
+    pg3-path=/var/lib/postgresql/16/main
     pg3-host-type=tls
     pg3-host-cert-file=/pg_ha/certs/${SRV_NAME}.crt
     pg3-host-key-file=/pg_ha/certs/${SRV_NAME}.key
@@ -243,7 +243,7 @@ Run the following command on `node1`, `node2` and `node3`.
     tls-server-auth=bkp-srv=cluster_1
 
     [cluster_1]
-    pg1-path=/var/lib/postgresql/11
+    pg1-path=/var/lib/postgresql/16/main
     ```
 
 4. Create the `systemd` unit file at the path `/etc/systemd/system/pgbackrest.service`
@@ -338,4 +338,4 @@ Run the following commands on the **backup server**
     $ sudo -iu postgres pgbackrest --stanza=cluster_1 expire --set=20230617-021338F
     ```
 
-[Test PostgreSQL cluster](ha-test.md){.md-button}
+[Test PostgreSQL cluster](ha-test.md){.md-button}