Tablespace Information

You ran:

psql -c “select oid, spcname, pg_tablespace_location(oid) from pg_tablespace”

Result:

OID	Tablespace Name	Location
1663	pg_default	(inside data directory)
1664	pg_global	(inside data directory)
16419	TBS2	/var/lib/pgsql/backup/TBS2
16420	TBS3	/var/lib/pgsql/backup/TBS3

So you have two external tablespaces: TBS2 and TBS3

1. Backup in TAR + Compressed Format

pg_basebackup -h localhost -p 5432 -U postgres -D /var/lib/pgsql/backup -Ft -z -Xs -P

Explanation of Parameters

Parameter	Meaning
-h localhost	Connect to PostgreSQL running on local host
-p 5432	PostgreSQL port number
-U postgres	User performing the backup (must have REPLICATION role)
-D /var/lib/pgsql/backup	Directory where backup files should be stored
-F t	Format = TAR archive
-z	Compress the TAR output (creates .tar.gz files)
-X s	Include WAL files in backup (stream mode)
-P	Show progress

 

2. Backup in Plain Directory Format

pg_basebackup -h localhost -p 5432 -U postgres -D /var/lib/pgsql/backup -Fp -Xs -P

Explanation

Parameter	Meaning
-F p	Format = Plain directory (exact data directory copy)
-Xs	Stream WAL files and include in backup directory
-P	Show progress

Important Note

Plain format will fail if tablespace directories already exist and are not empty.
This is why tablespace mapping is used.

3. Backup with Tablespace Mapping

 

Run backup with mapping

pg_basebackup -D /var/lib/pgsql/backup -F p -R -P -X stream \
–tablespace-mapping=/var/lib/pgsql/TBS1=/var/lib/pgsql/backup/TBS2 \
–tablespace-mapping=/var/lib/pgsql/TBS3=/var/lib/pgsql/backup/TBS3

Explanation of Tablespace Mapping

Parameter	Meaning
–tablespace-mapping=OLD=NEW	Redirects tablespace directory from its original location to new backup location

So we are saying:

Store /data_pgbench → /var/lib/pgsql/backup/data_pgbenchStore /data_pgtest  → /var/lib/pgsql/backup/data_pgtest

This ensures:

• No overwrite of existing tablespace directories
• Clean self-contained backup directory
• Safe restore on another server / instance