Code rollbacks are about immediate mitigation, not about pie in the sky snapshot rollback. If you are sane about deployment and don't go to 100% of traffic instantly, then halting a broken deploy and rolling back is certainly better than shifting into analysis mode.
> I'd rather stay broken a little longer for avoiding further complications!
Unfortunately analysis is slow and an unbounded process, and high leverage businesses where every second of downtime has actual measurable loss simply cannot accept this trade-off.
Good point. Few solutions are apt for every scale and every business!
OTOH, if you really essay a given deployment again and again, you can become really confident that the operation will succeed in production.
Real example: the most important feature I've developed this year has been put 5+ times in staging across a couple months. Every time I've asserted all kind of stuff, gathered feedback from the business owner, etc.
The deployment going bad in production is just not a possibility.
At a larger scale than mine, I would probably introduce 'dark launching' as well. That would further reduce the possibility of needing rollback.
> I'd rather stay broken a little longer for avoiding further complications!
Unfortunately analysis is slow and an unbounded process, and high leverage businesses where every second of downtime has actual measurable loss simply cannot accept this trade-off.