add small block about redis configuration

src/guides/v2.3/config-guide/redis/config-redis.md

@@ -16,7 +16,8 @@ Redis features include:
 *  Redis supports on-disk save and master/slave replication.
 
 {:.bs-callout-info}
-Starting in Magento 2.0.6, you can use either Redis or [memcached]({{ page.baseurl }}/config-guide/memcache/memcache.html) for session storage. Earlier issues with the Redis session handler and session locking have been resolved.
+Starting in Magento 2.0.6, you can use either Redis or [memcached]({{ page.baseurl }}/config-guide/memcache/memcache.html) for session storage. Earlier issues
+with the Redis session handler and session locking have been resolved.
 
 ## Install Redis {#config-redis-install}
 
@@ -27,6 +28,41 @@ Installing and configuring the Redis software is beyond the scope of this guide.
 *  [digitalocean](https://www.digitalocean.com/community/tutorials/how-to-install-and-use-redis)
 *  [Redis documentation page](http://redis.io/documentation)
 
+## Set up redis configuration {#config-redis-setup}
+
+Depending on your installation, you can usually find your Redis configuration at /etc/redis/redis.conf or /etc/redis/`port`.conf
+
+To optimize your Redis instance to your needs, you get best results when using a dedicated instance for each sessions, Magento cache and FPC.
+
+For sessions, it's recommended to enable persistence. This can either be done by regular RDB snapshots or by using the AOF persistence logs.
+You can get details of the advantages and disadvantages of RDB and AOF on the [Redis Persistence documentation](https://redis.io/topics/persistence).
+
+RDB (Redis Database File) snapshots store the complete database in a dump file after a given time, when a minimum number of keys have changed since the last save.
+This can be configured with the `save` setting inside `redis.conf`.
+
+AOF (Append Only File) stores each write operation sent to Redis in a journal file. This file ẃill be read by Redis on restart to restore the original dataset.
+
+It's possible to enable both RDB and AOF at the same time.
+
+For the cache instance, you should make sure the instance is set up to be large enough to store your whole Magento cache.
+The required size depends on different factors (like number of products and store views) but the required size of the file system cache gives you the order of
+magnitude. Persistence is not required here as the Magento cache can be restored. See also [Redis cache guide](https://redis.io/topics/lru-cache).
+
+For performance tuning you can also enable these settings for asynchronous deletion. This will not change the behavior of Redis (see also
+[redis news](http://antirez.com/news/93).
+
+```ini
+lazyfree-lazy-eviction yes
+lazyfree-lazy-expire yes
+lazyfree-lazy-server-del yes
+replica-lazy-flush yes
+```
+From redis 6.x onwards, you can also set
+
+```ini
+lazyfree-lazy-user-del yes
+```
+
 ## For more information
 
 You can find more information about configuring Redis from the following: