Documentation for media_storage_providers

[matrixbot]

This issue has been migrated from #7140.

---

I want to use the s3_storage_provider.S3StorageProviderBackend.

I configured it and when images are send over my synapse server they are also stored in the s3 bucket.
Here is how i configured it:

media_storage_providers:
- module: s3_storage_provider.S3StorageProviderBackend
  store_local: False
  store_remote: True
  store_synchronous: True
  config:
    bucket: synapse1
    endpoint_url: $HIDDEN_ENDPOINT
    access_key_id: $HIDDEN_KEY
    secret_access_key: $HIDDEN_KEY

But the images are still also stored locally on disk at /var/lib/matrix-synapse/media and if i remove the folder /var/lib/matrix-synapse/media the images are not shown anymore although they are still in the s3 bucket. So it seems to me that the s3_storage_provider.S3StorageProviderBackend does nothing but also store the data as a backup option?

I also could not find any documentation about media_storage_providers in this repo.
Can someone explain what they are and how they are supposed to work please.

My use case is that i want only to use the S3 Bucket and no local storage. Is this possible with media_storage_providers?