I actually think Redis really needs to trend towards a forkless approach for replication. Although copy-on-write provides a predictable form of memory usage, it does cause rather high memory utilization and requires a good bit of over provisioning.

There was an optimization built for Redis 7 where we actually start return copied memory pages back to the kernel, https://github.com/redis/redis/pull/8974, I wonder if the testing provided on Dragonfly includes this optimization.