How To Clone PostgreSQL Cluster from One Host to Another Using pg_basebackup (No Archive Mode)

Table of Contents

1. Goal
2. Environment (Source / Target)
3. Verify Existing Setup
4. Verify postgresql.conf
5. Verify pg_hba.conf
6. Verify Users
7. Directory Permissions
8. Take Backup
9. Verify Backup
10. Transfer Backup to Target
11. Prepare Target & Restore

                  11.1 Backup Target (Optional)
                  11.2 Stop PostgreSQL and Clean Directories
                  11.3 Restore Data and WAL
                  11.4 Set Permissions
                  11.5 Verify Restored Files
                  11.6 Create Symbolic Link for WAL

12. Start PostgreSQL on Target
13. Final Verification

In PostgreSQL, a cluster is a group of databases managed by one PostgreSQL server. This is just a standalone server, not like an Oracle RAC cluster.

1. Goal

1. Perform a consistent backup using pg_basebackup from lxicbpgdsgv01.
2. Restore the backup on lxicbpgdsgv02 without applying archived WALs.

2. Environment (Source / Target)

 3. Verify Existing Setup

[postgres@lxicbpgdsgv01 ~]$ psql
psql (17.6)
Type "help" for help.

postgres=# \l+
                                                                                       List of databases
   Name    |  Owner   | Encoding | Locale Provider |   Collate   |    Ctype    | Locale | ICU Rules |   Access privileges   |  Size   | Tablespace |                Description
-----------+----------+----------+-----------------+-------------+-------------+--------+-----------+-----------------------+---------+------------+--------------------------------------------
 dell      | postgres | UTF8     | libc            | en_SG.UTF-8 | en_SG.UTF-8 |        |           |                       | 7763 kB | pg_default |
 orcl      | postgres | UTF8     | libc            | en_SG.UTF-8 | en_SG.UTF-8 |        |           |                       | 7907 kB | pg_default |
 postgres  | postgres | UTF8     | libc            | en_SG.UTF-8 | en_SG.UTF-8 |        |           |                       | 492 MB  | pg_default | default administrative connection database
 template0 | postgres | UTF8     | libc            | en_SG.UTF-8 | en_SG.UTF-8 |        |           | =c/postgres          +| 7545 kB | pg_default | unmodifiable empty database
           |          |          |                 |             |             |        |           | postgres=CTc/postgres |         |            |
 template1 | postgres | UTF8     | libc            | en_SG.UTF-8 | en_SG.UTF-8 |        |           | =c/postgres          +| 7723 kB | pg_default | default template for new databases
           |          |          |                 |             |             |        |           | postgres=CTc/postgres |         |            |
(5 rows)

postgres=#

postgres=# \c dell
You are now connected to database "dell" as user "postgres".
dell=#

dell=# \db
       List of tablespaces
    Name    |  Owner   | Location
------------+----------+----------
 pg_default | postgres |
 pg_global  | postgres |
(2 rows)

dell=# 
dell=# \dn test
 List of schemas
 Name |  Owner
------+----------
 test | postgres
(1 row)

dell=#
dell=# \echo :AUTOCOMMIT
on
dell=#

dell=# CREATE TABLE test.emp ( name TEXT, designation TEXT, project TEXT, company TEXT);
CREATE TABLE
dell=# INSERT INTO test.emp VALUES ('Sugi', 'DBA', 'Jetstar', 'iGATE');
INSERT 0 1
dell=# INSERT INTO test.emp VALUES ('Teja', 'DBA', 'RCM', 'iGATE');
INSERT 0 1
dell=# INSERT INTO test.emp VALUES ('RAJ', 'DBA', 'RCM', 'iGATE');
INSERT 0 1
dell=#
dell=# select * from test.emp;
 name | designation | project | company
------+-------------+---------+---------
 Sugi | DBA         | Jetstar | iGATE
 Teja | DBA         | RCM     | iGATE
 RAJ  | DBA         | RCM     | iGATE
(3 rows)

dell=#

dell=# \c orcl
You are now connected to database "orcl" as user "postgres".
orcl=#
orcl=# \dt
            List of relations
 Schema |    Name     | Type  |  Owner
--------+-------------+-------+----------
 public | sample_data | table | postgres
(1 row)

orcl=#
orcl=# select count(*) from sample_data;
 count
-------
  1000  <----- 
(1 row)

orcl=#

4. Verify postgresql.conf

postgres=# SHOW wal_level;
 wal_level
-----------
 replica  <---- Should be replica
(1 row)

postgres=#
postgres=# SHOW max_wal_senders;
 max_wal_senders
-----------------
 10 <----- 
(1 row)

postgres=# SHOW archive_mode;
 archive_mode
--------------
 off  <----- No archive log mode
(1 row)

postgres=# show archive_command;
 archive_command
-----------------
 (disabled)
(1 row)

postgres=#

5. Verify pg_hba.conf

# TYPE  DATABASE        USER            ADDRESS             METHOD
# Local connections for replication (for pg_basebackup run locally)
local   replication     all                                 trust

# Remote connections for replication (for pg_basebackup run remotely)
#host    replication     repl_user       192.168.2.52/32     scram-sha-256

6. Verify user permissions:REPLICATION or SUPERUSER required

postgres=# \du
                             List of roles
 Role name |                         Attributes
-----------+------------------------------------------------------------
 postgres  | Superuser, Create role, Create DB, Replication, Bypass RLS

postgres=#

7. Directory Permissions for Backup

[postgres@lxicbpgdsgv01 ~]$ ls -ld /pgBackup/pgsql17/backup/
drwx------. 2 postgres postgres 6 Oct  9 18:46 /pgBackup/pgsql17/backup/
[postgres@lxicbpgdsgv01 ~]$

8. Take Backup

• Want symlinks preserved → use -Fp
• Want single tar archive → use -Ft, but recreate symlinks after restore, for pg_wal

[postgres@lxicbpgdsgv01 ~]$ nohup pg_basebackup -U postgres -D /pgBackup/pgsql17/backup/pg_basebackup_lxicbpgdsgv01_10sep2025 -Ft -Xs -P > /pgBackup/pgsql17/backup/pg_basebackup_lxicbpgdsgv01_10sep2025.log 2>&1 &
[1] 4438
[postgres@lxicbpgdsgv01 ~]$

9. Verify Backup

[postgres@lxicbpgdsgv01 ~]$ cat /pgBackup/pgsql17/backup/pg_basebackup_lxicbpgdsgv01_10sep2025.log
nohup: ignoring input
waiting for checkpoint
133816/536026 kB (24%), 0/1 tablespace
299960/536026 kB (55%), 0/1 tablespace
447864/536026 kB (83%), 0/1 tablespace
536037/536037 kB (100%), 0/1 tablespace
536037/536037 kB (100%), 1/1 tablespace
[postgres@lxicbpgdsgv01 ~]$

[postgres@lxicbpgdsgv01 ~]$ ls -lrth /pgBackup/pgsql17/backup/pg_basebackup_lxicbpgdsgv01_10sep2025
total 540M
-rw-------. 1 postgres postgres 524M Oct  9 18:56 base.tar  
-rw-------. 1 postgres postgres 223K Oct  9 18:56 backup_manifest
-rw-------. 1 postgres postgres  17M Oct  9 18:56 pg_wal.tar 
[postgres@lxicbpgdsgv01 ~]$

10. Transfer Backup to Target

[postgres@lxicbpgdsgv01 pg_basebackup_lxicbpgdsgv01_10sep2025]$ scp * 192.168.2.52:/pgbackup/pgsql17/backup/
postgres@192.168.2.52's password:  
backup_manifest                   100%  222KB  30.7MB/s   00:00
base.tar                          100%  523MB  74.0MB/s   00:07
pg_wal.tar                        100%   16MB  43.5MB/s   00:00
[postgres@lxicbpgdsgv01 pg_basebackup_lxicbpgdsgv01_10sep2025]$

11. Prepare Target & Restore

-- List Source Backup files 
[postgres@lxicbpgdsgv02 ~]$ ls -lrth /pgbackup/pgsql17/backup
total 540M
-rw-------. 1 postgres postgres 223K Oct  9 19:08 backup_manifest
-rw-------. 1 postgres postgres 524M Oct  9 19:08 base.tar
-rw-------. 1 postgres postgres  17M Oct  9 19:08 pg_wal.tar
[postgres@lxicbpgdsgv02 ~]$

11.1 Backup Target (Optional)

nohup pg_basebackup -U postgres -D /pgbackup/pgsql17/pg_basebackup_lxicbpgdsgv02_10sep2025 -Ft -Xs -P > /pgbackup/pgsql17/pg_basebackup_lxicbpgdsgv02_10sep2025.log 2>&1 &

-- Verify Tablespaces path -- It's pg_default in our case
-- Verify WAL File (Redo log files) location 

[postgres@lxicbpgdsgv02 ~]$ ls -ltr /pgdata/pgsql17/data/pg_wal
lrwxrwxrwx. 1 postgres postgres 18 Oct  9 17:37 /pgdata/pgsql17/data/pg_wal -> /pgwal/pgsql17/wal
[postgres@lxicbpgdsgv02 ~]$

11.2 Stop PostgreSQL and Clean Directories

-- Stop PostgreSQL DB Cluster
[root@lxicbpgdsgv02 ~]# systemctl stop postgresql-17.service
[root@lxicbpgdsgv02 ~]#
[root@lxicbpgdsgv02 ~]# ps -ef | grep postgres
root       10259    7832  0 19:20 pts/0    00:00:00 grep --color=auto postgres
[root@lxicbpgdsgv02 ~]#

-- Remove all from Data directory 

[postgres@lxicbpgdsgv02 ~]$ rm -rf /pgdata/pgsql17/data/*
[postgres@lxicbpgdsgv02 ~]$ ls -ltr /pgdata/pgsql17/data/
total 0
[postgres@lxicbpgdsgv02 ~]$


-- Remove all from WAL directory 

[postgres@lxicbpgdsgv02 ~]$ rm -rf /pgwal/pgsql17/wal/*
[postgres@lxicbpgdsgv02 ~]$ ls -ltr /pgwal/pgsql17/wal/
total 0
[postgres@lxicbpgdsgv02 ~]$

11.3 Restore Data and WAL

-- List source backup files

[postgres@lxicbpgdsgv02 ~]$ cd /pgbackup/pgsql17/backup/
[postgres@lxicbpgdsgv02 backup]$ ls -ltr
total 552652
-rw-------. 1 postgres postgres    227724 Oct  9 19:08 backup_manifest
-rw-------. 1 postgres postgres 548901888 Oct  9 19:08 base.tar
-rw-------. 1 postgres postgres  16778752 Oct  9 19:08 pg_wal.tar
drwxr-xr-x. 3 postgres postgres        18 Oct  9 19:32 data_lxicbpgdsgv02_old
[postgres@lxicbpgdsgv02 backup]$

# Restore DATA Directory 
[postgres@lxicbpgdsgv02 ~]$ nohup tar -xvf /pgbackup/pgsql17/backup/base.tar -C /pgdata/pgsql17/data > /pgbackup/pgsql17/backup/base_restore.log 2>&1 &
[1] 11289
[postgres@lxicbpgdsgv02 ~]$


# Restore WAL Directory 

[postgres@lxicbpgdsgv02 ~]$ nohup tar -xvf /pgbackup/pgsql17/backup/pg_wal.tar -C /pgwal/pgsql17/wal > /pgbackup/pgsql17/backup/pg_wal_restore.log 2>&1 &
[1] 11304
[postgres@lxicbpgdsgv02 ~]$

-- OR -- 

# Restore base and WAL archives sequentially in a single command

nohup bash -c "tar -xvf /pgbackup/pgsql17/backup/base.tar -C /pgdata/pgsql17/data && tar -xvf /pgbackup/pgsql17/backup/pg_wal.tar -C /pgwal/pgsql17/wal" > /pgbackup/pgsql17/backup/fulltar_restore.log 2>&1 &

11.4 Set Permissions

[postgres@lxicbpgdsgv02 ~]$ chown -R postgres:postgres /pgdata/pgsql17/data
[postgres@lxicbpgdsgv02 ~]$ chmod 700 /pgdata/pgsql17/data
[postgres@lxicbpgdsgv02 ~]$
[postgres@lxicbpgdsgv02 ~]$ chown -R postgres:postgres /pgwal/pgsql17/wal
[postgres@lxicbpgdsgv02 ~]$ chmod 700 /pgwal/pgsql17/wal
[postgres@lxicbpgdsgv02 ~]$

11.5 Verify Restored Files

[postgres@lxicbpgdsgv02 ~]$ ls -ltr /pgdata/pgsql17/data
total 72
-rw-------. 1 postgres postgres    88 Sep 30 21:50 postgresql.auto.conf
drwx------. 2 postgres postgres    18 Sep 30 21:50 pg_xact
-rw-------. 1 postgres postgres     3 Sep 30 21:50 PG_VERSION
drwx------. 2 postgres postgres     6 Sep 30 21:50 pg_twophase
drwx------. 2 postgres postgres     6 Sep 30 21:50 pg_tblspc
drwx------. 2 postgres postgres     6 Sep 30 21:50 pg_subtrans
drwx------. 2 postgres postgres     6 Sep 30 21:50 pg_stat_tmp
drwx------. 2 postgres postgres     6 Sep 30 21:50 pg_snapshots
drwx------. 2 postgres postgres     6 Sep 30 21:50 pg_serial
drwx------. 2 postgres postgres     6 Sep 30 21:50 pg_notify
drwx------. 4 postgres postgres    36 Sep 30 21:50 pg_multixact
-rw-------. 1 postgres postgres  2640 Sep 30 21:50 pg_ident.conf
drwx------. 2 postgres postgres     6 Sep 30 21:50 pg_dynshmem
drwx------. 2 postgres postgres     6 Sep 30 21:50 pg_commit_ts
-rw-------. 1 postgres postgres 30702 Oct  7 18:20 postgresql.conf.bkp
drwx------. 2 postgres postgres    84 Oct  9 00:01 log
-rw-------. 1 postgres postgres  1169 Oct  9 16:31 postgresql.conf.bkp_10sep2025
-rw-------. 1 postgres postgres  1171 Oct  9 16:32 postgresql.conf
drwx------. 7 postgres postgres    59 Oct  9 18:08 base
drwx------. 2 postgres postgres     6 Oct  9 18:44 pg_stat
-rw-------. 1 postgres postgres    30 Oct  9 18:44 current_logfiles
-rw-------. 1 postgres postgres  5600 Oct  9 18:53 pg_hba.conf
-rw-------. 1 postgres postgres     0 Oct  9 18:56 tablespace_map
drwx------. 2 postgres postgres     6 Oct  9 18:56 pg_replslot
drwx------. 4 postgres postgres    68 Oct  9 18:56 pg_logical
-rw-------. 1 postgres postgres   227 Oct  9 18:56 backup_label
drwx------. 4 postgres postgres    45 Oct  9 20:06 pg_wal <--- Created as Directory, instead of symbolic link 
drwx------. 2 postgres postgres  4096 Oct  9 20:06 global
[postgres@lxicbpgdsgv02 ~]$
[postgres@lxicbpgdsgv02 ~]$ ls -ltr /pgwal/pgsql17/wal
total 16384
-rw-------. 1 postgres postgres 16777216 Oct  9 18:56 000000010000000000000045
[postgres@lxicbpgdsgv02 ~]$

Please note:

--- Want symlinks preserved → use -Fp
--- Want single tar archive → use -Ft, but recreate symlinks after restore, for pg_wal

11.6 Create Symbolic Link for WAL

[postgres@lxicbpgdsgv02 ~]$ ls -ld /pgdata/pgsql17/data/pg_wal
drwx------. 4 postgres postgres 45 Oct  9 20:06 /pgdata/pgsql17/data/pg_wal
[postgres@lxicbpgdsgv02 ~]$
[postgres@lxicbpgdsgv02 ~]$ rm -rf /pgdata/pgsql17/data/pg_wal
[postgres@lxicbpgdsgv02 ~]$ ln -s /pgwal/pgsql17/wal /pgdata/pgsql17/data/pg_wal
[postgres@lxicbpgdsgv02 ~]$
[postgres@lxicbpgdsgv02 ~]$ ls -ld /pgdata/pgsql17/data/pg_wal
lrwxrwxrwx. 1 postgres postgres 18 Oct  9 21:04 /pgdata/pgsql17/data/pg_wal -> /pgwal/pgsql17/wal
[postgres@lxicbpgdsgv02 ~]$ 
[postgres@lxicbpgdsgv02 ~]$ cd /pgwal/pgsql17/wal
[postgres@lxicbpgdsgv02 wal]$ ll
total 16384
-rw-------. 1 postgres postgres 16777216 Oct  9 18:56 000000010000000000000045
[postgres@lxicbpgdsgv02 wal]$

12. Start PostgreSQL on Target — no recovery needed.

[root@lxicbpgdsgv02 ~]# systemctl start postgresql-17.service
[root@lxicbpgdsgv02 ~]# systemctl status postgresql-17.service
● postgresql-17.service - PostgreSQL 17 database server
     Loaded: loaded (/usr/lib/systemd/system/postgresql-17.service; enabled; preset: disabled)
     Active: active (running) since Thu 2025-10-09 21:06:08 +08; 5s ago
       Docs: https://www.postgresql.org/docs/17/static/
    Process: 12375 ExecStartPre=/usr/pgsql-17/bin/postgresql-17-check-db-dir ${PGDATA} (code=exited, status=0/SUCCESS)
   Main PID: 12380 (postgres)
      Tasks: 7 (limit: 20496)
     Memory: 33.6M
        CPU: 114ms
     CGroup: /system.slice/postgresql-17.service
             ├─12380 /usr/pgsql-17/bin/postgres -D /pgdata/pgsql17/data
             ├─12381 "postgres: logger "
             ├─12382 "postgres: checkpointer "
             ├─12383 "postgres: background writer "
             ├─12385 "postgres: walwriter "
             ├─12386 "postgres: autovacuum launcher "
             └─12387 "postgres: logical replication launcher "

Oct 09 21:06:06 lxicbpgdsgv02.rajasekhar.com systemd[1]: Starting PostgreSQL 17 database server...
Oct 09 21:06:06 lxicbpgdsgv02.rajasekhar.com postgres[12380]: 2025-10-09 21:06:06.781 +08 [12380] LOG:  redirecting log output to logging collector process
Oct 09 21:06:06 lxicbpgdsgv02.rajasekhar.com postgres[12380]: 2025-10-09 21:06:06.781 +08 [12380] HINT:  Future log output will appear in directory "log".
Oct 09 21:06:08 lxicbpgdsgv02.rajasekhar.com systemd[1]: Started PostgreSQL 17 database server.
[root@lxicbpgdsgv02 ~]#

13. Final Verification

[postgres@lxicbpgdsgv02 ~]$ psql
psql (17.6)
Type "help" for help.

postgres=# \l+
                                                                                       List of databases
   Name    |  Owner   | Encoding | Locale Provider |   Collate   |    Ctype    | Locale | ICU Rules |   Access privileges   |  Size   | Tablespace |                Description
-----------+----------+----------+-----------------+-------------+-------------+--------+-----------+-----------------------+---------+------------+--------------------------------------------
 dell      | postgres | UTF8     | libc            | en_SG.UTF-8 | en_SG.UTF-8 |        |           |                       | 7609 kB | pg_default |
 orcl      | postgres | UTF8     | libc            | en_SG.UTF-8 | en_SG.UTF-8 |        |           |                       | 7753 kB | pg_default |
 postgres  | postgres | UTF8     | libc            | en_SG.UTF-8 | en_SG.UTF-8 |        |           |                       | 492 MB  | pg_default | default administrative connection database
 template0 | postgres | UTF8     | libc            | en_SG.UTF-8 | en_SG.UTF-8 |        |           | =c/postgres          +| 7545 kB | pg_default | unmodifiable empty database
           |          |          |                 |             |             |        |           | postgres=CTc/postgres |         |            |
 template1 | postgres | UTF8     | libc            | en_SG.UTF-8 | en_SG.UTF-8 |        |           | =c/postgres          +| 7569 kB | pg_default | default template for new databases
           |          |          |                 |             |             |        |           | postgres=CTc/postgres |         |            |
(5 rows)

postgres=# \db
       List of tablespaces
    Name    |  Owner   | Location
------------+----------+----------
 pg_default | postgres |
 pg_global  | postgres |
(2 rows)

postgres=#
postgres=# \c dell
You are now connected to database "dell" as user "postgres".
dell=# \dt test.*
        List of relations
 Schema | Name | Type  |  Owner
--------+------+-------+----------
 test   | emp  | table | postgres
(1 row)

dell=#

dell=# select * from test.emp;  <---- We can see Data 
 name | designation | project | company
------+-------------+---------+---------
 Sugi | DBA         | Jetstar | iGATE
 Teja | DBA         | RCM     | iGATE
 RAJ  | DBA         | RCM     | iGATE
(3 rows)

dell=#
dell=# \c orcl
You are now connected to database "orcl" as user "postgres".
orcl=# \dt
            List of relations
 Schema |    Name     | Type  |  Owner
--------+-------------+-------+----------
 public | sample_data | table | postgres
(1 row)

orcl=#
orcl=# select count(*) from sample_data;
 count
-------
  1000 <----
(1 row)

orcl=#

Caution: Your use of any information or materials on this website is entirely at your own risk. It is provided for educational purposes only. It has been tested internally, however, we do not guarantee that it will work for you. Ensure that you run it in your test environment before using.

Thank you,
Rajasekhar Amudala
Email: br8dba@gmail.com
Linkedin: https://www.linkedin.com/in/rajasekhar-amudala/