Try to make the Elasticsearch storage requirement clear

doc/integration/elasticsearch.md

@@ -38,7 +38,7 @@ each node should have:
 
 - [Memory](https://www.elastic.co/guide/en/elasticsearch/guide/current/hardware.html#_memory): 8 GiB (minimum).
 - [CPU](https://www.elastic.co/guide/en/elasticsearch/guide/current/hardware.html#_cpus): Modern processor with multiple cores.
-- [Storage](https://www.elastic.co/guide/en/elasticsearch/guide/current/hardware.html#_disks): Use SSD storage. You will need enough storage for 50% of the total size of your Git repositories.
+- [Storage](https://www.elastic.co/guide/en/elasticsearch/guide/current/hardware.html#_disks): Use SSD storage. The total storage size of all Elasticsearch nodes is about 50% of the total size of your Git repositories. It includes one primary and one replica.
 
 A few notes on CPU and storage: