Manual:$wgMainCacheType/en

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).