z[Deprecated] Upgrading from Memcached to Redis

The following information is no longer relevant if you are on the current version of Pilothouse, and is only being kept around for legacy purposes.

Pilothouse is moving from Memcached to Redis as the default persistent object cache backend (https://stackoverflow.com/a/11257333).

If you have existing local sites that were created using Memcached as the object cache backened, you will need to perform the following steps on each of your sites in order to make them work with Redis.

First, update Pilothouse and make sure you are on the develop branch, then make sure you are using the latest Pilothouse PHP docker images which include the phpredis extension by running the following commands:

pilothouse down
pilothouse compose down --remove-orphans
pilothouse compose pull
pilothouse up

On each site, open wp-config.php and replace this:

global $memcached_servers;
$memcached_servers = [ 'default' => [ 'memcached:11211' ] ];

with this:

$redis_server = [ 'host' => 'redis' ];

Next, delete the wp-content/object-cache.php file, and replace it with the version from https://raw.github.com/pantheon-systems/wp-redis/master/object-cache.php.