Manual:$wgFileBackends

Details
This is an array of configuration arrays. Each backend configuration has the following parameters:
 * name
 * A unique name for the backend


 * class
 * The file backend class to use


 * wikiId
 * A unique string that identifies the wiki (container prefix)


 * lockManager
 * The name of a lock manager (see )


 *  Additional parameters are specific to the class used.