Sometimes it isn't worth the effort to fix the old, and instead just go to the new and improved.

When the load balancer for reddit broke once, we did't bother fixing it, we just replaced it with better (though untested) technology on the assumption it would work better. We figured it couldn't be any worse than it was, and we'd rather spend our limited time moving forward instead of treading water.

We considered this pretty seriously, and it might be required some day, but we think we'll be able to incrementally move toward a more highly available, better performing architecture without a continuity break.

Why not just port to the Reddit codebase? The functionality seems similar.

The HN code base is as much an experiment in Arc as it is a social news site. Also the feature set is surprisingly different (although I wish some of the features were here like comment collapsing and async comment submission).

Maybe it would be too much work to rewrite the specific logic that prevents HN 'manipulation' for reddit? Although I suppose much of the behavior and target audience is similar...

reddit.com/r/hackernews the new hacker news.

You might be joking, but in case not: reddit's code base is open source, so others can use it without moving the community under the reddit umbrella.

When we upgraded LBs we didn't have a continuity break. We just flipped the IP when it was ready.

For most DB upgrades we did dual writing so we didn't have to have a break.