add small block about redis configuration (#8073)

* Update config-redis.md

add quick explanation how to setup Redis

* Update config-redis.md

Fix line length

* Update config-redis.md

fix markdown
Add more explanation about AOF and RDB

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

* RDB written out correctly

*  Reformulated size explanation in config-redis.md to be more clear

Co-authored-by: Barny Shergold <[email protected]>
Co-authored-by: Margaret Eker <[email protected]>

Author: 3 people

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

@@ -16,7 +16,7 @@ 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 from 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 +27,37 @@ 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 in one of the following files: `/etc/redis/redis.conf` or `/etc/redis/<port>.conf`
+
+To optimize the Redis instance for your requirements, you get best results by using a dedicated instance for each session, Magento cache and FPC.
+
+For sessions, we recommend that you enable persistence to copy Redis data to disk using either of the following persistence options: regular Redis Database Backup (RDB) snapshots, or Append Only File (AOF) persistence logs.
+
+*  RDB (Redis Database Backup) 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. Use the `save` setting inside the `redis.conf` file to configure this setting.
+
+*  AOF (Append Only File) stores each write operation sent to Redis in a journal file. Redis reads this file on restart only and uses it to restore the original dataset.
+
+You can also enable both the RDB and AOF options at the same time. For additional details including the advantages and disadvantages of the persistence options, see the [Redis Persistence documentation](https://redis.io/topics/persistence).
+
+For the cache instance, set up the instance so that it is large enough to store your entire Magento cache.
+Size requirements depend on different factors like the number of products and store views. As a starting point, you can use the size of the cache folder on your file system.  For example, if the `var/cache` folder on your file system is  5 GB, set up your Redis instance with at least 5 GB to start. Persistence is not required for the cache instance because the Magento cache can be restored. See also [Redis cache guide](https://redis.io/topics/lru-cache).
+
+For performance tuning, you can also enable the following settings for asynchronous deletion. These settings do not change the behavior of Redis. See also [redis news](http://antirez.com/news/93) for details about asynchronous deletion.
+
+```ini
+lazyfree-lazy-eviction yes
+lazyfree-lazy-expire yes
+lazyfree-lazy-server-del yes
+replica-lazy-flush yes
+```
+On Redis 6.x and later, you can also add the following value:
+
+```ini
+lazyfree-lazy-user-del yes
+```
+
 ## For more information
 
 You can find more information about configuring Redis from the following: