Backing up Discourse with RDS

| community | devops | aws |

We are launching a community site with Discourse at CircleCI and I ran into some issues with performing backups.

Since we want to be #webscale, rather than installing Discourse using the easy Docker method, we opted to split up the services on AWS.

We are using EC2, RDS, ElasticCache, ELB and S3 for backups. When I initially launched PostgreSQL on RDS I just picked the latest version (9.4 at time of writing) and didn’t put much thought into it. The problem is that the version of pg_dump inside the Docker container provided by Discourse is 9.3.  Apparently you are not able to do a pg_dump when your client and server are mismatched.

When you try to do this, you get a sad error that states:

aborting because of server version mismatch

In order to fix this, we need to upgrade the client version on the Docker container (or alternatively avoid this all together by using the same version of PostgreSQL on RDS). Since it is easier to update the client than downgrade RDS, I opted to upgrade the client.

To do this:

  1. Log into the EC2 Instance that is running Discourse
  2. Go to the Discourse install location (mine is in /var/docker)
  3. Enter the container with:
    sudo ./launcher enter app
    
  4. Upgrade the version of PostgreSQL client
    apt-get install postgresql-9.4
    
  5. Swap out the pg_dump symbolic link for the newer version
        ln -s /usr/lib/postgresql/9.4/bin/pg_dump /usr/bin/pg_dump
    
  6. Perform your  backup
When you update the Docker container for the next release you will likely have to repeat these steps until Discourse gets to the same version of PostgreSQL as the one you chose on RDS.

Thank you for reading! Share your thoughts with me on bluesky, mastodon, or via email.

Check out some more stuff to read down below.

Most popular posts this month

Recent Favorite Blog Posts

This is a collection of the last 8 posts that I bookmarked.

Articles from blogs I follow around the net

Occupation and Preoccupation

Here’s Jony Ive in his Stripe interview: What we make stands testament to who we are. What we make describes our values. It describes our preoccupations. It describes beautiful succinctly our preoccupation. I’d never really noticed the connection between th…

via Jim Nielsen’s Blog July 17, 2025

What do we do when the facts don't matter?

As a journalist by training, I have what you might call an addiction to facts. I believe that there are things that are true and things that are not, and that we can determine one from the other through observation, rational thought, and meticulous resear…

via The Torment Nexus July 17, 2025

Back to the Future

This past weekend, I decided to take a trip down memory lane and take a look at the evolution of this blog’s design over the years (with a little help from the Wayback Machine). While I’ve really enjoyed the challenge of making an obsessively backwards co…

via flower.codes July 17, 2025

Generated by openring