how to restore postgreSQL 8.3 DB after unistall

Question

I have unfortunately broken my old machine with postgres 8.3 on debian 6.0, I found a directory backup of postgresql database files, and i try to copy them on the new machine with a new version of postgres 9.1, but postgres on start fail with error:

[FAIL with server 2022-05-05 14:22:42 GMT DETAIL: The data directory was initialized by PostgreSQL version 8.3, which is not compatible with this version 9.1.21. ... failed! failed!

I found several guides explaining how to upgrade from an older version to a newer one, but these only work if you have the old version installed and working, in my case I can't install the old one anymore as postgresql 8.3 is no longer supported. How can I recover the old db and data?

Update..., this all command that I runnig:

#initialize db
/usr/local/pgsql/bin/initdb -D pgdata
#copy original files
cp -r /var/lib/postgresql/8.3/main/* pgdata/
#start server
/usr/local/pgsql/bin/pg_ctl -D ./pgdata -l logfile start
>server starting
#check log
tail logfile
>   FATAL:  database "DB2" does not exist
>   FATAL:  database "DB0" does not exist
>   FATAL:  database "DB1" does not exist
>   FATAL:  database "DB2" does not exist
>   FATAL:  database "DB0" does not exist
>   FATAL:  database "DB1" does not exist
>   FATAL:  database "DB2" does not exist
>   FATAL:  database "DB0" does not exist
>   FATAL:  database "DB1" does not exist
>   FATAL:  database "DB2" does not exist

/usr/local/pgsql/bin/psql
psql: FATAL:  database "postgres" does not exist
/usr/local/pgsql/bin/pg_dumpall > db.out
>   pg_dumpall: could not connect to database "template1": FATAL:  database "template1" does not exist

@Laurenz Albe

Answer 1

You have to install 8.3, probably from source, on a machine with the same architecture. Then copy the complete data directory to that machine and start the server on it.

Now pg_dumpall the cluster and restore it to PostgreSQL v14.

You should not run initdb at all. Instead,

cp -r /var/lib/postgresql/8.3/main pgdata

If the data directory was complete, you should be able to start the server after that.