About Denbun system
Denbun saves any data in the database.
Therefore, it simply separates cgi programs and data.
However the cgi programs use OS file system for temporary files.

Backup and restore data
Since Denbun saves any data in the database, you can backup "dnpwmldb". (exception (*1))
To backup data, you can use pg_dump command or other standard way provided by PostgreSQL.
Please refer the PostgreSQL documentation.

*1 Users' photos registered by the administrators are not stored in the database. If you wish to backup the data, backup the directory "dnpwml/dnpwmlfile".

[Example for backup]
pg_dump -b -Fc -U postgres dnpwmldb > dnpwmldb.pgdmp

To restore the data, you can use pg_restore command or other standard way provided by PostgreSQL.
Please refer the PostgreSQL documentation.

[Example for restore]
dropdb -U postgres dnpwmldb
pg_restore -C -Fc -U postgres -d template1 ./dnpwmldb.pgdmp
psql -U postgres -d dnpwmldb < Installation directory(*1)/admintools/sql/uninstall_textsearch_ja.sql  (*2)
psql -U postgres -d dnpwmldb < Installation directory(*1)/admintools/sql/textsearch_ja.sql
psql -U postgres -d dnpwmldb < Installation directory(*1)/admintools/sql/denbun_ja.sql

*1	Specify the installation directory according to your installation environment. In Windows:   C:\Inetpub\Scripts\dnpwml In Linux:   /var/www/cgi-bin/dnpwml
*2	Even though the following errors occurred, there is no problem. ERROR: text search configuration "pg_catalog.japanese" does not exist ERROR: text search parser "pg_catalog.japanese" does not exist ERROR: text search dictionary "japanese_stem" does not exist ERROR: text search template "pg_catalog.mecab" does not exist

However if you use other backup tool, please follow the way provided by the tool.