fixup! [AMORO-3404] Correct the description about MySQL usage

Author: klion26

amoro-docs/content/admin-guides/deployment-on-kubernetes.md

@@ -156,8 +156,8 @@ ingress:
 
 ### Configure the database.
 
-AMS default is to use Derby database for storage. When the pod is destroyed, the data will also disappear.
-In production environments, we recommend using a RDBMS as the storage for system data, you can ref to [Database Configuration](/deployment/#configure-system-database) for more detail.
+AMS uses embedded [Apache Derby](https://db.apache.org/derby/) as its backend storage by default.
+In production environments, we recommend using a RDBMS(Relational Database Management System) with higher availability guarantees as the storage for system data, you can ref to [Database Configuration](/deployment/#configure-system-database) for more detail.
 
 ```yaml
 amoroConf: 

amoro-docs/content/admin-guides/deployment.md

@@ -98,7 +98,7 @@ Make sure the port is not used before configuring it.
 
 ### Configure system database
 
-Amoro used `Derby` as the backend storage default, so you can use `Derby` directly without any additional configuration. 
+AMS uses embedded [Apache Derby](https://db.apache.org/derby/) as the backend storage by default, so you can use `Derby` directly without any additional configuration. 
 
 You can also configure a relational backend storage as you needed.