If you have multiple WordPress websites on your server, enabling cache at the same time will have the same cache name for each of the WordPress installations! It does not matter, which caching engine you use, Redis or Memcached.
In order to prevent the cache from purging on all WordPress websites, when you try or, purge the cache for a single WordPress website, you should define it through the wp-config.php file! You just need to add a constant to the wp-config.php file in the root directory of your WordPress website:
define('WP_CACHE_KEY_SALT', 'hostwave.xyz');
Make sure to replace the string with "hostwave.xyz", you may replace it with your own domain/subdomain of WordPress installation! Remember it, the string should be different for each of the WordPress installations!
Or, you can use WP_REDIS_PREFIX instead of WP_CACHE_KEY_SALT (if you're using Redis caching engine only!)
