How to find the correct Joomla log path
When migrating a Joomla 3 installation, either from one hosting server to another, or when uploading to your webserver or if you are changing the base installation for one reason or another - you need to make sure you that you update the configuration.php file correctly. One of the things which needs to be correct is the $tmp_path and $log_path. If these are not correct, your Joomla installation will look like its working correctly but it might start throwing strage errors such as
0 Cannot open file for writing log
or some other error, when trying to install new extensions, free Joomla templates, modules or plugins.
However, sometimes it may not be so easy to determine the exact path you need to use before the /logs and /tmp - especially if you are on shared or on a new hosting server. Fortunately, there is an easy way to discover what the home path is:
Copy the following code into a text editor and save the file as absolute.php
IMPORTANT: For security reasons, delete this file as soon as you have copied the path!
Now that you know the exact path make sure you edit the configuration.php file to the absolute path + /logs and absolute path + .tmp as follows where <absolute path> is the path given to you by the above code
public $log_path = '<absolute path>/logs';
public $tmp_path = '<absolute path>/tmp';