But integrating those two repositories with all the automated workflows is quite a headache. Jenkins won't automatically switch over to another git backend if one fails. Other automated tools like code review are mostly relying on a centralized repostiory. I don't see any simple solution to solve these issues. Bitbucket, GitHub, GitLab don't have any easy fallback solutions when you relying core workflows on their services.
Self hosting is maybe one solution (we do this with bitbucket), but this requires major administrative effort to keep it running reliably (always available, no data losses on hardware/software failures).
