cache by file system
1. Give proper permission to the folder named "qa-cache" on where you install Q2A
2. Add this line on qa-config.php define('QA_BLOBS_DIRECTORY', '/path/to/writable_blobs_directory/');
you need to give full directory, for example:
define('QA_CACHE_DIRECTORY', '/home/q2a/public_html/qa-cache/');
3. Go to yoursite/admin/caching
4. tick "Enable caching" box, choose "Caching driver" and set cache time, done
cache by memcached
1) make sure you have memcached module installed and enabled on your server.
2)Go to yoursite/admin/caching
3)4. tick "Enable caching" box, choose "memcached" and set cache time, done