How do I back up my Cloudant database to COS?

Cloudant offers a facility to create backups called couchbackup. It works by taking a copy of a single Cloudant database. It writes it to a local file by default, but it can be configured to write it to Cloud Object Storage (COS).

This can be done either in two separate operations, first creating the file and then uploading it to COS; or in one operation by streaming the database content directly to COS.

There are examples of how to do both of those here.

Remember that IBM COS is fully compatible with AWS S3 so you can store your backups in either of them.