Instances: redis-1 = General, redis-2 = User data, memcached = Transients

object-cache.config.php

<?php

$config = [
	'pools' => [
		// Default/fallback controller.
		'General'    => [
			'method'        => 'Redis',
			'config'        => [
				'scheme' => 'tcp',
				'host'   => 'redis-1',
				'port'   => 6379
			],
			'prerequisites' => [
				'class' => 'Redis',
			],
			'groups'        => [
				''
			],
		],
		'Users'    => [
			'method'        => 'Redis',
			'config'        => [
				'scheme' => 'tcp',
				'host'   => 'redis-2',
				'port'   => 6379
			],
			'prerequisites' => [
				'class' => 'Redis',
			],
			'groups'        => [
				'users',
				'user_meta',
				'userlogins',
			],
		],
		'transients' => [
			'method'        => 'Memcached',
			'config'        => [
				'servers' => [
					[
						'memcached',
						11211
					],
				],
			],
			'prerequisites' => [
				'class' => 'Memcached',
			],
			'groups'        => [
				'transient',
				'site-transient',
			],
		],
	],
];