Our front end Nignx servers are loaded to a target of 40% CPU. However when we reload Nginx (for example adding/removing server blocks), we get a high CPU spike - lasts about 3-5 mins usually. Nignx does not pull from cache/Redis during this time and provides little optimised content. Eventually (maybe once all the workers have reloaded??), Nignx starts pulling optimised content from cache/Redis and everything settles. Depending on traffic we have to plan for server reloads because the CPU spike can be enough to cause very slow performance at best and intermittent 502/gateway style errors at worst.
My question: Is there a way to minimise the CPU spike on reload and does Apache/Redis do this too?