I don' know if I understand aright. Normally one shouldn't change constants in file defines.php or am I wrong?

So, I entered new line/absolute path in my configuration.php

public $cache_path = '/absolute/path/to/my/joomla34/mycache';

Created new folder /mycache/ in Joomla root.
Activated caching in configuration.

And all worked as expected. All cached folder/files in /mycache/ and could clear cache in Joomla backend (administrator/index.php?option=com_cache).

The path constants can be overridden (see https://github.com/joomla/joomla-cms/blob/staging/index.php#L25-L34)

Unfortunately, I don't see an easy way to fix this issue, so if you want to use custom path for cache, you should use the solution which @bertmert mentioned above

The path constants can be overridden (see https://github.com/joomla/joomla-cms/blob/staging/index.php#L25-L34)

I didn't know that. Thank you.

@bertmert - "public $cache_path = '...'" worked fine! This var ($cache_path) no by default in configuration.php... Where I can get full list variable's allowed for configuration.php?

Thank.

Closing as the issue is fixed.

@remotehelp

Where I can get full list variable's allowed for configuration.php?

try: https://raw.githubusercontent.com/joomla/joomla-cms/staging/installation/configuration.php-dist