Under Nginx/PHP-FPM, I can't get PHP errors logged to craft/storage/runtime/logs/phperrors.log as they should be.
Initially, errors weren't logging anywhere, but I discovered I needed:
catch_workers_output = yes in our PHP-FPM config.
Errors are now logging to /var/log/php7.0-fpm.log, but not to Craft's custom location.
I'm only 80% confident in this answer, but I'm pretty sure that runtime PHP ini_set calls won't work with nginx running with FastCGI (which is what Craft uses to change the error_log path.
Try setting that path directly in your /etc/php5/fpm/php.ini file.
error_log (or maybe anything?) in /etc/php/7.0/fpm/php-fpm.conf will override even what is set in your pool conf. (e.g. /etc/php/7.0/fpm/pool.d/mysite.conf), .user.ini, and of course runtime ini_set. What I did was comment out the error_log line in /etc/php/7.0/fpm/php-fpm.conf and added php_value[error_log] = ... to Craft's storage path in my pool config. Seems backward...what is especially confusing is looking at phpinfo, the values appear to be overriding, but wont actually work!
– Tim Kelty
Aug 11 '16 at 14:49
