Online migrations at scale 9 years ago
We're doing nearly the exact same approach in my office out of necessity.
We "allowed" small amounts of downtime previously (say 10-15 minutes at a time for migrations), but over the last year as our customer base has expanded, the window has shrunk smaller and smaller as to avoid service disruptions.
We're now at a stage where downtime is effectively not allowed anymore, so we've taken to this approach (make a new table, dual write new records, then write all the old records, remove references to the old table) to mitigate our downtime.
It's nice to know that other companies have taken this approach as well, my team honestly didn't know if we were doing it "properly" or not (if there is such a thing as properly)