With the continued growth of cloud technology and the need for businesses to leverage the power that comes with faster processing times, better analysis capacity, and vast storage options, migrating your organization’s SQL database to Microsoft Azure becomes paramount.
I. Understanding Online Migration
Online migration refers to the process of moving data from one location to another without significantly affecting the system operation during the process. In the realm of SQL databases, online migration insinuates moving your data to a more reliable, secure, and efficient cloud platform – in this case, Microsoft Azure. This means continued usage of your databases while the migration happens, thus minimal downtime and interruption to your services.
II. Implementing an Online Migration Strategy
When looking to implement an online migration strategy administering Microsoft Azure SQL solutions, it is essential to follow the suitable process for success. Here is a step-by-step guide:
- Assess Azure Readiness:
- Monitored the source SQL Server for a minimum of one week.
- Completed the installation of the Azure SQL Database or Azure SQL Managed Instance.
- Ensure you have all necessary administration rights for the target databases.
- Plan Migration Strategy:
- Offline Migration: Ideal when the database is relatively small, and brief application downtime is acceptable during the migration process.
- Online Migration: Suits when the database is larger, and no significant downtime is tolerable during the migration process.
- Deploy Azure Database Migration Service (DMS):
- Migrate Database Schema:
- Migrate Data:
- Test:
- Complete Migration:
Evaluate the readiness of your Azure SQL Database or Azure SQL Managed Instance for migration. Tools such as the Azure Database Migration Assessment are useful here. Guidelines include:
Carefully plan your migration strategy, considering your resources, costs, and potential downtime. Two main migration approaches include:
Microsoft Azure provides Azure DMS that supports both types of migrations (Offline and Online). For an online migration, DMS creates an initial snapshot of your database, starts continuous sync for the changes, and lets you manually trigger the cutover when you’re ready.
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Before the actual data migration, ensure to migrate the schema of your source SQL Server database to the target Azure SQL Database. You can use the Data Migration Assistant (DMA) to do this.
After migrating the schema, it’s time to migrate the database using Azure Database Migration Service.
Carry out a series of tests on your new Azure SQL to ensure everything works as expected. Confirm the database tables, triggers, views, etc., are working correctly.
After testing, and no issues found, complete the migration process. At this stage, the target Azure SQL database will be in sync with your source database.
III. Benefits Of Implementing An Online Migration Strategy
Implementing an online migration strategy to Microsoft Azure SQL solutions come with several benefits tied to efficient cloud computing, which include:
- Continuous database operation during migration.
- High availability and disaster recovery.
- Improved scalability and performance.
- Cost-effective storage solutions.
- Enhanced data security and compliance.
With the right strategy, the procedure of implementing an online migration for Administering Microsoft Azure SQL solutions is straightforward. Understanding how to plan, set up the environment, migrate data, and validate the migrated objects is key for anyone preparing for the DP-300 exam.
Practice Test
True/False: Azure SQL Database supports online migration, allowing you to migrate on-premises SQL Server databases to Azure SQL Database with minimal downtime.
- True
- False
Answer: True
Explanation: Azure SQL Database supports Database Migration Service (DMS) that helps you simplify, guide, and automate your database migration process to Azure.
Microsoft’s service for Azure database migration is referred to as _____.
- a) Azure Database Migration Service
- b) Azure Data Lake Store
- c) Azure Data Factory
Answer: a) Azure Database Migration Service
Explanation: Azure Database Migration service simplifies, guides, and automates the process of migrating databases to Azure.
True/False: During an online migration, the SQL Server database being migrated is locked and inaccessible.
- True
- False
Answer: False
Explanation: Azure’s Data Migration Service allows for “online” migrations, which permit the applications to continue writing to databases during the migration.
The Azure Database Migration Service (DMS) supports which types of migrations?
- a) Online migrations
- b) Offline migrations
- c) Both
Answer: c) Both
Explanation: Azure DMS supports both online and offline migrations. You choose the type of migration that best suits your needs.
Which Azure feature allows minimally disruptive migration that can migrate your SQL server database while maintaining existing services?
- a) Offline migration
- b) Online migration
- c) Passive migration
Answer: b) Online migration
Explanation: In an online migration, the database continues to be operational during the migration, allowing minimal disruption.
True/False: The offline migration in Azure is suited for large-scale database migration that have a limited migration window.
- True
- False
Answer: True
Explanation: Due to the downtime involved during the migration process, offline migrations are typically used for larger databases that can withstand periods of inaccessibility.
The Database Migration Service in Azure supports migration from which of the following?
- a) SQL Server
- b) MySQL
- c) PostgreSQL
- d) All of the above
Answer: d) All of the above
Explanation: Azure DMS supports various source and target pairings, including SQL Server, MySQL, PostgreSQL, and others.
True/False: It’s recommended to perform an offline migration for your SQL database if your applications cannot tolerate any downtime.
- True
- False
Answer: False
Explanation: If your applications cannot tolerate any downtime, it’s recommended to perform an online migration, which allows the applications to continue writing to the databases during the migration.
Which of the following Azure services is used to move your databases to the cloud while keeping the applications at their existing location?
- a) Azure Site Recovery
- b) Azure Migrate
- c) Azure Database Migration Service
- d) Azure Data Factory
Answer: c) Azure Database Migration Service
Explanation: Azure DMS is a fully managed service designed to enable seamless migrations from multiple database sources to Azure data platforms with minimal downtime.
An ongoing migration from on-premise SQL Server to Azure SQL Database can be monitored using which of these?
- a) Azure Monitor
- b) Azure SQL Analytics
- c) Azure Purview
- d) Azure Synapse Analytics
Answer: a) Azure Monitor
Explanation: Azure Monitor allows you to monitor the ongoing data migration processes from on-premise SQL Server databases to Azure SQL Database.
Interview Questions
What is the purpose of online migration strategy in Microsoft Azure SQL?
The purpose of the online migration strategy in Microsoft Azure SQL is to ensure a smooth transition from on-premise SQL server to Azure SQL Database, with virtually no downtime.
Name two methods for implementing an online migration strategy in Azure SQL?
The two methods for implementing an online migration strategy in Azure SQL are Azure Database Migration Service (DMS) and Transactional Replication.
What is the Azure Database Migration Service (DMS)?
Azure Database Migration Service (DMS) is a fully managed service designed to enable seamless migrations from multiple database sources to Azure Data platforms with minimal downtime.
What is the main prerequisite for utilizing Azure DMS for online migrations?
The main prerequisite for utilizing Azure DMS for online migrations is that the SQL Server version should be 2005 or later, and the on-premise server must be accessible from the Azure service.
What is the purpose of the Transactional Replication method in an online migration strategy?
Transactional Replication method allows an option to migrate databases with minimal downtime by continually synchronizing changes from the source SQL Server database.
How does the Transactional Replication method work in online migration?
Transactional Replication works by the Distributor continually updating the changes from the published database (source database) to the Subscriber (Azure SQL database).
In an online migration strategy, what is the role of Azure VPN Gateway or ExpressRoute?
Azure VPN Gateway or ExpressRoute establishes a dedicated network connection from the on-premise network to Azure, which could be used during the migration, ensuring security and better performance.
Can the Full-Text Search feature directly migrate in an online migration strategy to Azure SQL Database?
No, Azure SQL Database does not support Full-Text Search feature. We will need to refactor this feature before migrating the database.
Is it possible to implement an online migration strategy in Azure SQL without downtime?
Yes, by using Azure Database Migration Service and Transactional Replication, it is possible to minimize or avoid downtime.
How does the Azure Database Migration Service handle the migration of large databases?
Azure Database Migration Service can handle large database migrations by chunking the data migration operation. Data is migrated in smaller sets, rather than as one large operation.
What is the main advantage of implementing an online migration strategy?
The main advantage of implementing an online migration strategy is the minimization of downtime, enabling businesses to continue operating as normal during the migration.
What type of Microsoft SQL Server workloads can you migrate to Azure using an online migration strategy?
You can migrate all SQL Server workloads to Azure SQL Database, Azure SQL Managed Instance, and SQL Server on Azure Virtual Machine using an online migration strategy.
Is Azure Active Directory integration supported in Azure SQL Database?
Yes, Azure Active Directory is supported in Azure SQL Database. It allows for seamless identity management and security.
When should Azure SQL Database be used rather than SQL Server on an Azure Virtual Machine?
Azure SQL Database should be used when you want a fully managed platform-as-a-service (PaaS) that automatically handles most database management functions such as upgrading, patching, backups, and monitoring. SQL Server on an Azure Virtual Machine would be the choice when you need to control the details of the database engine or migrate a large number of existing SQL Server databases to Azure.
What is the role of network latency in online migration strategy?
Network latency can slow down the migration process, especially while transferring large databases. Tunneling the data through Azure ExpressRoute or VPN Gateway provides an optimized, faster path for migration.
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