cagliostr uses sqlite3 and litestream to ship WAL backups directly to S3.
Another relay written in C++: https://github.com/mattn/cagliostr
The last time someone showed up with a C++ relay it went like this:
nostr:npub1zl3g38a6qypp6py2z07shggg45cu8qex992xpss7d8zrl28mu52s4cjajh
Discussion
Can it use litestream to replicate the database to other running instances of cagliostr? nostr:npub1937vv2nf06360qn9y8el6d8sevnndy7tuh5nzre4gj05xc32tnwqauhaj6