I'm currently writing a book for PragProg called Building Distributed Services with Go (though it mostly applies to other languages too) that's walks you through building a distributed database from scratch. You can sign up on this mailing list to know when it's available: https://travisjeffery.us4.list-manage.com/subscribe?u=1e3ff7....
Yeah I'm discussing with my editor now about when to put out the beta it'll be out either after we finish editing the chapter I just finished writing or the next one. So pretty soon. I hope to have the whole book finished by July but that's a bit more TBD up to how soon I finish writing the last few chapters.