Where does nginx store the rewrite_log?

by default turning "rewrite_log on;" affects only if your config file "error_log logs/error.log notice;" already marks which non-default event levels do you need to be logged.

"Setting a certain log level will cause all messages of the specified and more severe log levels to be logged."

So, first "error_log logs/error.log notice;" then "rewrite_log on;" and error.log starts receiving rewriting logging

http://nginx.org/en/docs/ngx_core_module.html#error_log http://nginx.org/en/docs/http/ngx_http_rewrite_module.html#rewrite

If rewrite_log on; is used then the rewrite information will be logged to error_log at notice level. There is no separate log file.