Hi everyone. Welcome to the second chapter in our Tencent Cloud Solutions Architect professional course, cloud migration. At the end of this chapter, you'll be able to understand and apply various cloud migration assessment methods, understand the overall process of cloud migration. Become familiar with Tencent Cloud's migration tools and understand the entire cloud migration process. In this chapter, we'll cover five sections, assessment of cloud migration, overall process of cloud migration, overview of migration tools, common migration modes and case studies. This video will cover the first section, assessment of cloud migration. Subsequent videos will cover the remaining four sections. Okay, let's get started with Section 1, assessment of cloud migration. In this video, we'll cover how to determine the cloud migration mode. How to assess whether the business is suitable for cloud migration and the information to be assessed for cloud migration. Cloud migration can be implemented in different modes according to the migration source and target. The migration source can either be a local IDC, private cloud or public cloud and the target can be either a public cloud or a private cloud. The scope of this chapter covers cloud migration to Tencent public cloud. Now, the first thing to consider during cloud migration is what can be migrated and how, which requires assessing whether the business is suitable for cloud migration and how to perform the migration. Applications or systems that are suitable for cloud migration have no special dependencies on hardware, with the ability to adopt modular design or add notes to improve the processing capabilities. Other applications or systems may require transformation including platform refactoring, system upgrades or application refactoring for transformation from light coupling architecture into distributed architecture. Applications or systems that are unsuitable for cloud migration include AIX applications, proprietary systems or systems that require external hardware. The assessment process to determine whether the business is suitable for cloud migration is shown here in a flow chart. To see whether the existing system can be migrated to the cloud directly or if it requires transformation, simply follow the flow chart cases for each scenario. If the existing system is used for the long term, there is no risk. The utilization is between 60 and 80%. The number of concurrent users exceeds 50% and it is scaled as the pressure increases, then you can migrate to the cloud directly. Additionally, if the existing system is not used for a long term will not be deactivated soon and can be ported quickly. Then you can also migrate to the cloud directly. You can refer to the chart for information on the other use cases of cloud migration. The information to be assessed for cloud migration can be categorized into either computing, network, storage, database or application. For computing, the OS, CPU, memory, system disk, data disk and computing resource utilization, need to be assessed for cloud migration, so that the appropriate CVM instances, cloud disk types and OS can be selected. For network, the IP address, public network address and the number of network interfaces, must all be assessed for cloud migration to plan reasonable VPCs. And to select the appropriate network services, bandwidth and billing mode. For storage, filesystem, archive, backup, log and other storage resources should be assessed to select the appropriate storage services such as CFS, CAS, COS and CLS. For databases, the database type, version, size and access permissions must be assessed to select the appropriate TencentDB services and data transfer method. For applications, the current business conditions, user access, future development trends, resource configuration information, application software versions, software installation packages and application dependency. Should be assessed to accurately select the region and number of Tencent Cloud service instances as well as determine how to implement cloud deployment based on information of the software to be installed. Other information to be assessed for cloud migration includes the system importance, system deployment mode and business condition assessment. System importance includes content such as system use period, user use period and allowed maximum downtime. System deployment mode includes centralized and decentralized deployment, as well as deployment location. The business condition assessment consists of determining if it is used for the long term, the impact of system downtime, the number of concurrent users and system resource utilization. Other things to consider are if it supports transformation and if it can be migrated to the cloud smoothly.