Hey, I'm the author of this blog post, I'll try to respond to your questions: > Wow, I didn't think that PHP application code would be such a bottleneck. Maybe

Hey, I'm the author of this blog post, I'll try to respond to your questions: > Wow, I didn't think that PHP application code would be such a bottleneck. Maybe it's not that, but if the entire codebase is written in PHP, and you replace it all in one shot, you just get such an improvement. But I thought DBs, etc. would play a bigger role Indeed front-end servers not the only bottleneck to handle more queries. We also made data migrations on mysql databases to optimize memory utilization, two months after the php7 migration. Code migration and the validation that we hadn't introduced new regressions / errors by redirecting a small percentage of the traffic through two servers with php7 configured during few days before full deployment. Full deployment on our production farm (more than 250 servers) was done in less than two hours with the possibility of rollback) >> It took less than a week to migrate our codebase (a 10 years old PHP monolith)... >> And it took 4 hours to migrate our custom extensions. >That seems like a very small amount of work; I'm impressed at how smooth a transition that must've been. We used phan and phpcs to discover our incompatibilities, it doesn't find 100% of problems, but it really reduced time to find where there was backward incompatibilities. It's a first step before unit tests / small load test on production. I wrote a small blog post on how to use this tools to migrate your applications : https://medium.com/@colomb.thomas/php7-how-to-migrate-your-application-88154d99a88a#.qxbjwsatl https://medium.com/@colomb.thomas/php7-how-to-migrate-your-a... Thanks!