In some situations, if not most, you should avoid using if blocks. There are two main issues that occur if you do so, regardless of the Nginx build you are using.
There are some cases where if is used inappropriately, in a way that risks saturating your storage device with useless checks:
location / {
# Redirect to index.php if the requested file is not found
if (!-e $request_filename) {
rewrite ^ index.php last;
}
}With such a configuration as the preceding one, every single request received by Nginx will trigger a complete verification of the directory tree for the requested filename, thus requiring multiple storage disk access system calls. If you test /usr/local/nginx/html/hello.html, Nginx will check /, /usr, /usr/local, /usr/local/nginx, and so on. In any case, you should avoid resorting to such a statement by filtering the file type beforehand (for instance, by making such a check only if the requested file matches specific extensions...