I have seen many people warn customers about a few minutes of downtime while running EasyApache on their servers. So they always suggest to run it is off-peak hours. Though it is not recommend to recompile such mission critical stuff during peak traffic hours ( which may put some server load as well ) it will not cause a few minutes of down-time normally. cPanel has built EasyApache Apache package intelligently, so that even though the build fails it will switch Apache/PHP back to the working versions. Also it will do only single service restart at the end, which is only defined service interruption while an EasyApache. But there are other possibilities as well, if Apache restarts during EasyApache build. Like if we restart Apache while building mod_sec module, it will throw syntax error if you have mod_sec directives defined for of of your websites. That is because Apache off-load mod_sec module just to recompile and the error remains until the so file rebuild by EasyApache. That will persists only for a few seconds and if we try to restart Apache during that time it will fail. So in such a case, we will have to force another manual start for Apache after building specific .so file.