> I would say that the trick is not to do the rewrite. You refactor each part until the entire system is rewritten.
This is exactly the right way to approach this. The best way I’ve seen to rewrite a complex system is to literally work off a branch and deploy it in QA beside the old version. The hardest part is figuring out the right way you want to direct traffic to the “new version”.
My team inherited a massive system that was the key revenue generator for a multi billion dollar company. It was an operational nightmare from deployments to stability. It had at least 1 24 hour outage that was nearly impossible to root cause.
We slowly chipped away at it for 8 months running in parallel in QA until we were satisfied that it was functionally equivalent. Started running traffic in prod while we tuned it to start taking real traffic and had the whole thing replaced in 18 months.
The system was replaced, is handling 2X the load in prod of the old system and hasn’t had an outage years
This is exactly the right way to approach this. The best way I’ve seen to rewrite a complex system is to literally work off a branch and deploy it in QA beside the old version. The hardest part is figuring out the right way you want to direct traffic to the “new version”.
My team inherited a massive system that was the key revenue generator for a multi billion dollar company. It was an operational nightmare from deployments to stability. It had at least 1 24 hour outage that was nearly impossible to root cause.
We slowly chipped away at it for 8 months running in parallel in QA until we were satisfied that it was functionally equivalent. Started running traffic in prod while we tuned it to start taking real traffic and had the whole thing replaced in 18 months.
The system was replaced, is handling 2X the load in prod of the old system and hasn’t had an outage years