This add-on uses Credis with a custom cache provider for Redis (based off Cm_Cache_Backend_Redis). For best performance, install the php extension: phpredis. You must have a Redis instance installed, this is likely not possible with shared hosting. While XenForo 2 has a redis connector, it requires phpredis. This add-on does not. Feature overview: A pure php redis connector | High availability support | Exposes redis cache object for use for use by other add-ons | Implements some minor caching of forum thread counts