Write permissions

These two:

wp-content/object-cache.php
wp-content/.redis-write-test.tmp

This means you need write permissions for the folder “wp-content” – that’s bad! In secure installations, this folder is write-protected. The files must therefore be in a subdirectory for which you can safely set up write permission, for example “/wp-content/cache/”.

Can the path be configured or do I need another plug-in?

The wp-content/object-cache.php is required by WordPress, we have no control over it.

You can safely ignore the “Dateisystem” warning.

This is not correct. The file “/wp-content/object-cache.php” does not come from WordPress but from your plugin:

Author: Till Krüss
Plugin Name: Redis Object Cache Drop-In

I can release write permission for defined directories, but not for the “wp-content” folder, as this is too dangerous.
The two files “object-cache.php” and “.redis-write-test.tmp” are generated by your plugin and for this you need write permission for the folder “wp-content”, which is not good.

Please save the two files in a separate directory or under “/wp-content/cache/”.

This is not correct. The file “/wp-content/object-cache.php” does not come from WordPress but from your plugin.

Correct, what Till meant was that WordPress determines the /wp-content/object-cache.php path and we cannot change it.

Please save the two files in a separate directory or under “/wp-content/cache/”.

We have no control over the wp-content/object-cache.php, it is hard-coded by WordPress core.

Would you like to to disable the .redis-write-test.tmp check?