## Overview

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> [!NOTE]
> This lab only supports Chrome browser.

TiDB is a distributed database which provides you the flexibility of scaling in/out the computing (SQL layer) or the storage layer (TiKV layer) easily. When scaling in the computing layer, your application needs to follow best practice, to achieve zero downtime. In this lab, we discuss those best practices.

### Prerequisites

+ You should finish the lab [Database Seamless Scalability](/labs/demo_009), before working on this one.

### Tasks

+ Understand the best practice when scaling in the SQL layer with network load balancer
+ Observe the zero downtime feature when scaling in the SQL layer with TiProxy

> [!TIP]
> Click **Start** to launch the lab environment.
> Once the environment is ready, the resources assigned to your hands-on session will be populated with the actual values, so you can follow the lab guide step-by-step to complete the practice.