Ask Sendai

The Guardian migrated their CMS’s datastore in 2018 from a self-managed MongoDB cluster to PostgreSQL on Amazon RDS for a fully managed solution. The team did an API-based migration without any downtime. Guardian’s in-house CMS – called Composer – which stores articles, blog content, photo galleries and video was originally built on top of MongoDB as a datastore. This was preceded by a vendor software backed by an Oracle database.

In April the Guardian switched off the Mongo DB cluster used to store our content after completing a migration to PostgreSQL on Amazon RDS. This post covers why and how At the Guardian, the majority of content – including articles, live blogs, galleries and video content – is produced in our in-house CMS tool, Composer. This, until recently, was backed by a Mongo DB database running on AWS. This database is essentially the “source of truth” for all Guardian content that has been published online – approximately 2.