Store migration backend

This sounds extremely complex, inefficient and hacky.

If the sync features to support “Upgrade by replacement” (which are simpler and more usefull) this becomes redundant.

Provide a special store backend that wraps two other stores. This would allow online migrations from one store to another.

Primary concerns are:

  • Re-sharding collections in the event of storage format changes (i.e, organisations are added).
  • Move to other technologies: SQL solutions like Vitess.


  • Obviously the complexity in guaranteeing no data loss or corruption.
  • How to deal with mostly read-only data?
    • Assumed a copy on write system, should it become a copy on read?
    • Iterate through data and insert if missing?