Manual:$wgLocalisationCacheConf

Details
Localisation cache configuration. Associative array with keys:
 * class: The class to use. May be overridden by extensions.
 * store: The location to store cache data. May be 'files', 'db' or 'detect'. If set to "files", data will be in CDB files in the directory specified by $wgCacheDirectory. If set to "db", data will be stored to the database. If set to "detect", files will be used if $wgCacheDirectory is set, otherwise the database will be used.
 * storeClass: The class name for the underlying storage. If set to a class name, it overrides the "store" setting.
 * manualRecache: Set this to true to disable cache updates on web requests. Use maintenance/rebuildLocalisationCache.php instead.