Let's face it, major version upgrades can be a pain. Most people are familiar with the dump/restore method, but if your database happens to be larger than a few GB, the downtime required for dump/restore is likely going to exceed your maximum maintenance window.
We'll briefly explore upgrade options including dump/restore, pg_upgrade and logical replication tools like Slony and why I think Slony is currently the best option. Then we'll run through a tutorial on how to use slony for a major version upgrade with minimal downtime.
You can find the scripts used in the demos here: