Manual:$wgMainCacheType

Details
Allows to configure the object cache used.

Here are the keys available by default (defined as constants in Defines.php):
 * – Do not cache (default).
 * – Use  or  if they are set to something other than   or  . Otherwise use  .
 * – Use APCu or WinCache if available.
 * – Use if available. Servers must additionally be specified in .
 * – Use the database table .
 *  Warning:  This could potentially be slower than no caching, i.e..

See  for an example of a custom cache backend (e.g. Redis).