Grafana Mimir, touted as the most scalable and performant open-source time series database, offers a straightforward migration process from Cortex, as demonstrated in a video tutorial that shows how to transition in under four minutes using Jsonnet to generate the necessary configurations. Initially, Cortex handles the dashboards, but post-migration, Grafana Mimir becomes the backend, showcasing features like query sharding and a two-stage compactor. The tutorial series, which includes "Introducing Grafana Mimir" and "Getting started with Grafana Mimir," supports users in this transition, with further resources available through webinars, documentation, and community discussions. Grafana Cloud facilitates access to these capabilities with a free tier and various plans to accommodate different needs.