I have a production Geth node whose blockchain occupies around ~600 GB. I'm trying to figure out how to free up disk space. I know I can remove the blockchain and start fast sync from scratch, but that will take some time (probably more than a day) and it is not acceptable for a production node that is expected to be up 24/7. I can bring it down but for a couple of hours at the most. So my question is how to reduce blockchain size with a minimal downtime?
I was considering starting a new Geth node in parallel and have it fully sync, and then migrate the keys from the old node to the new one. But is there a better approach?