Create multiple Postgres instances on same machine

Question

To test streaming replication, I would like to create a second Postgres instance on the same machine. The idea is that if it can be done on the test server, then it should be trivial to set it up on the two production servers.

The instances should use different configuration files and different data directories. I tried following the instructions here http://ubuntuforums.org/showthread.php?t=1431697 but I haven't figured out how to get Postgres to use a different configuration file. If I copy the init script, the scripts are just aliases to the same Postgres instance.

I'm using Postgres 9.3 and the Postgres help pages say to specify the configuration file on the postgres command line. I'm not really sure what this means. Am I supposed to install some client for this to work? Thanks.

Answer 1

I assume you can work your way out on using postgresql utilities.

Create the clusters

$ initdb -D /path/to/datadb1 $ initdb -D /path/to/datadb2 

Run the instances

$ pg_ctl -D /path/to/datadb1 -o "-p 5433" -l /path/to/logdb1 start $ pg_ctl -D /path/to/datadb2 -o "-p 5434" -l /path/to/logdb2 start 

Test streaming

Now you have two instances running on ports 5433 and 5434. Configuration files for them are in data dirs specified by initdb. Tweak them for streaming replication.
Your default installation remains untouched in port 5432.