Once you've created your directory, adding the tablespace is simple:
CREATE TABLESPACE new_tablespaceLOCATION '/usr/local/pgsql/new_tablespace';
The command to remove the tablespace is also simple and is as follows:
DROP TABLESPACE new_tablespace;
Every tablespace has a location assigned to it, with the exception of the pg_global and pg_default default tablespaces, for shared system catalogs and all other objects, respectively. They don't have a location because they live in a subdirectory of the data directory.
A tablespace can be dropped only when it is empty, so how do you know when a tablespace is empty?
Tablespaces can contain both permanent and temporary objects. Permanent data objects are tables, indexes, and TOAST objects. ...
