Port changes in two-level-cache article from 2.4

src/guides/v2.3/config-guide/cache/two-level-cache.md

@@ -7,14 +7,14 @@ functional_areas:
   - Cache
 ---
 
-Caching allows us to reduce network traffic between the remote cache storage and Magento. A standard Magento instance transfers around 300kb per request, and traffic may quickly grow to over ~1000 requests in some situations.
+Caching enables a reduction in network traffic between the remote cache storage and Magento. A standard Magento instance transfers around 300kb per request, and traffic may quickly grow to over ~1000 requests in some situations.
 
 To reduce the network bandwidth to Redis, we can store cache data locally on each web node and use the remote cache for two purposes:
 
 -  To check the cache data version, ensuring we have the latest cache stored locally.
 -  If the data is out of date, transfer the latest cache from the remote machine to the local machine.
 
-Magento stores the hashed data version in Redis, with the suffix ':version' appended to the regular key. In case of an outdated local cache, we tranfer the data to the local machine with a cache adapter.
+Magento stores the hashed data version in Redis, with the suffix ':version' appended to the regular key. In case of an outdated local cache, the data is transferred to the local machine with a cache adapter.
 
 ## Configuration example
 
@@ -51,10 +51,11 @@ Magento stores the hashed data version in Redis, with the suffix ':version' appe
 
 Where:
 
--  `backend` is our remote L2 cache implementation.
+-  `backend` is the remote L2 cache implementation.
 -  `remote_backend` is the remote cache implementation: Redis or MySQL.
 -  `remote_backend_options` are Redis or MySQL-specific options.
--  `local_backend` is the local cache implementation: Cm_Cache_Backend_File or the APC adapter
+-  `local_backend` is the local cache implementation: `Cm_Cache_Backend_File` or the APC adapter.
+-  `cache_dir` is a directory where the local cache will be stored. It is suggested to use `/dev/shm/`.
 
 We recommend the use of Redis for remote caching - `\Magento\Framework\Cache\Backend\Redis`, and the File cache implementation - `Cm_Cache_Backend_File` as the local cache.
-We also recommend the use of the `cache preload` feature, as it will drastically decrease the pressure on Redis.
+We also recommend the use of the [`cache preload`]({{page.baseurl}/config-guide/redis/redis-pg-cache.html#redis-preload-feature) feature, as it will drastically decrease the pressure on Redis. Do not forget to add suffix ':version' for preload keys.