## Overview > [!NOTE] > This lab only supports Chrome browser. This lab explores **TiDB Cloud resilience against data center-level failures**. You will run the hands-on steps on **TiDB Self-Managed** (not inside a TiDB Cloud cluster) because TiDB Cloud is a fully managed service—you cannot SSH into individual PD, TiKV, or TiDB nodes to see how placement, replication, and failover work. Deploying TiDB Self-Managed in this lab lets you observe those components one by one and understand the same distributed architecture that TiDB Cloud relies on. The TiDB cluster is deployed across three Availability Zones, each corresponding to a subnet. You will simulate a network blackout in Subnet 1. This will disconnect one TiDB server, one TiKV server, and one PD server from the cluster. Even when an entire availability zone is lost, the cluster keeps serving traffic: database clients automatically connect to the remaining TiDB server instances without waiting for a monolithic server-side failover to finish—the same behavior your applications get on TiDB Cloud. ![80%](https://lab-static.pingcap.com/quick-demo/demo_001_en.png) ### What you will learn - How multi-AZ placement of PD, TiKV, and TiDB underpins TiDB Cloud resilience to data center failures. - How Raft replication and a stateless SQL layer let the cluster keep running when one zone is isolated. - Why application clients can keep reading and writing through healthy TiDB nodes—the guarantee TiDB Cloud inherits. ### Tasks - Review the TiDB cluster status and topology. - Blockade the network communication for an entire availability zone. - Observe and verify that the TiDB cluster maintains functionality when an entire availability zone is inaccessible. > [!TIP] > Click **Start** to launch the lab environment. > Once the environment is ready, select **Next** on the bottom toolbar to advance to **Module 1**. > And, follow the step-by-step lab guide to connect to the hands-on environment and begin your tasks.