Troubleshoot a migration

These may hinge on issues about performance, security, capacity, agility, or other related factors. Addressing these potential challenges entails a clear understanding of the problems and executing mitigation strategies. In this article, we will walk through several steps you can take to troubleshoot a few common migration issues encountered in the DP-300 Administering Microsoft Azure SQL Solutions exam.

Dependencies

Among the most crucial aspects of troubleshooting are dependencies. Unraveling dependencies is required to understand interactions in the environment. Not doing this will possibly lead to data inconsistencies or even data loss. Here is how you can detect dependencies during a migration.

If using SSMS (SQL Server Management Studio), you can evaluate dependencies using the built-in tool. Right-click on an object, select “View Dependencies,” and an overview of all dependent objects will be displayed.

Performance Issues

Performance problems can often stem from inappropriate database sizes and service tiers, improper configurations or inefficient queries. When troubleshooting performance issues, consider using Azure SQL Database’s built-in intelligent performance features such as:

• Performance Overview: Provides an insight into the workload, identifies disruptive events and helps you to dig deeper into specific areas.
• Query Performance Insight: Helps you to understand the longest-running queries.
• Automatic Tuning: Provides peak performance and stable workloads through artificial intelligence.

Connectivity

You may sometimes have connectivity issues when you are trying to migrate your databases. Azure SQL provides a diagnostic utility known as “SQL Connectivity Checker” which can diagnose common issues that may affect your server and database connectivity. You can download it from the official Microsoft downloads website.

Security Policies

Another possible problem could come from security or firewall settings. Azure SQL has a fairly good set of features for security integration, ranging from firewall rules to login credentials and permissions. Checking these elements and ensuring they are configured correctly can save you from unexpected issues during your migration.

Data Migration Assistant (DMA)

The Data Migration Assistant (DMA) is a Microsoft tool designed to simplify and streamline database structural assessments for upgrading to Azure SQL. Running DMA before actual migration can save you from some unexpected problems. After running a DMA assessment, review the guide for any problems and fix them before carrying out the migration.

Troubleshooting Migration Failures

With Azure Database Migration Service (DMS), you can monitor the status and result of each migration activity by querying the monitoring data. Here is a simple example:

sql
SELECT
command_type,
state,
percent_complete,
start_time,
total_elapsed_time,
[text]
FROM sys.dm_exec_requests
CROSS APPLY sys.dm_exec_sql_text(sql_handle);

Finally, Microsoft documentation has useful resources for troubleshooting a migration, including a comprehensive guide with detailed instructions and steps to help you diagnose and resolve issues. Note the error codes and messages that occur during the migration process and use the guide to help you investigate the underlying problems.

Remember, every migration is unique. Always document the process and learn from each migration. Not only will this help you streamline future migrations, but it will also provide a valuable resource when troubleshooting.

Practice Test

True or False: Troubleshooting migration problems is only done after the migration has been completed.

• True
• False

Answer: False

Explanation: Troubleshooting can be done before, during and after migration to ensure a smooth movement of data and services.

In any migration process, it’s essential to have ________ before beginning.

• A. Backup of data
• B. SQL Server
• C. Azure Synapse
• D. All of the above

Answer: A. Backup of Data

Explanation: Having a backup of data is essential before beginning any migration process. It ensures that you will not lose any important data during the migration process.

True or False: Azure Site Recovery is used to troubleshoot a migration.

• True
• False

Answer: True

Explanation: Azure Site Recovery provides disaster recovery capabilities, enabling users to work through issues as they arise, making it a valuable troubleshooting tool.

What can be the main reason for data migration failure?

• A. Network issues
• B. Insufficient resource allocation
• C. Poor planning
• D. All of the above

Answer: D. All of the above

Explanation: All these can be potential reasons for the migration failure. Good planning, resource allocation, and stable networks are crucial for successful migration.

The Azure Migration Assessment tool can identify potential issues with migration.

• A. True
• B. False

Answer: A. True

Explanation: The Azure Migration Assessment tool helps identify potential issues in the pre-migration phase.

Azure Migrate is a service that:

• A. Identifies migration issues
• B. Provides guidance for migration
• C. Migrates data
• D. All of the above

Answer: D. All of the above

Explanation: Azure Migrate is a comprehensive service that identifies migration issues, provides guidance for migration and helps to migrate data.

Corrupted data can be migrated and fixed later.

• A. True
• B. False

Answer: B. False

Explanation: It’s essential to fix corrupted data before migration. Otherwise, it can lead to serious issues like data loss or system crashes.

For troubleshooting SQL Server migrations, DMV queries are useful.

• A. True
• B. False

Answer: A. True

Explanation: Dynamic Management View (DMV) queries provide information about the SQL Server instance which can be helpful in troubleshooting.

True or False: The Azure portal provides a centralized location for monitoring the progress of data migration and troubleshooting any issues.

• True
• False

Answer: True

Explanation: Azure portal has built-in all necessary toolkits and dashboards for monitoring and troubleshooting.

Data Migration Assistant (DMA) is used to:

• A. Advance Migration
• B. Access Cloud data
• C. Assist in migration troubleshooting
• D. Build new data

Answer: C. Assist in migration troubleshooting

Explanation: DMA helps to detect compatibility and functionality issues that can impact database behaviour in Azure SQL. It also provides recommendations to fix these issues, thereby assisting in migration troubleshooting.

Azure SQL migration can be done without any downtime.

• A. True
• B. False

Answer: A. True

Explanation: Using the Azure Database Migration Service, live migrations with near-zero downtime can be achieved.

A migration project can be initiated without a strict roles and responsibility chart.

• A. True
• B. False

Answer: B. False

Explanation: Clear identification and delineation of roles and responsibilities helps in better coordination, efficient troubleshooting and overall successful migration.

Prioritizing data during migration can help in optimizing the migration process.

• A. True
• B. False

Answer: A. True

Explanation: Prioritizing data helps to focus on mission critical data first, ensuring its smooth transition and thereby better optimizing the migration process.

Communication to stakeholders is not a part of migration troubleshooting.

• A. True
• B. False

Answer: B. False

Explanation: Keeping stakeholders updated about the migration process, potential issues and resolutions is a crucial part of migration troubleshooting.

Appropriate use of Azure SQL Data Sync can help in troubleshooting migration.

• A. True
• B. False

Answer: A. True

Explanation: Azure SQL Data Sync allows for synchronization of data across different SQL databases which can be leveraged to mitigate certain migration-associated issues.

Interview Questions

What should you do if you experience a failure during data migration?

If a failure occurs during data migration, you should review the error logs. Investigate the possible reasons for the failure and check networking connectivity, target database settings, and the credentials you provided.

How can you verify if the migration of a SQL Server database to Azure SQL Database was successful?

You can verify the success of a migration using the Data Migration Assistant. It includes a validation feature that conducts a thorough comparison of the source and target databases to ensure the migration was successful.

Can the Azure Database Migration Service migrate the SQL Server logins and SQL Server Agent jobs?

No, the Azure Database Migration Service does not migrate SQL Server logins and SQL Server Agent jobs. Admins should manually recreate these aspects in the Azure SQL Database.

What would you do if you encounter performance issues after migrating a database to Azure?

If performance issues occur after migration, you can use Azure’s SQL Database Advisor. It will analyze your database’s workload and suggest optimization actions.

What is a common cause for a ‘connection failure’ status when using the Azure Database Migration Service?

A common cause for a ‘connection failure’ status can be due to incorrect login credentials, incorrect server name, or network connectivity issues.

What should you do when you notice a slowdown in migration speed?

You can scale up your target server’s compute size temporarily during the migration if you notice a slowdown in speed. After the migration, scale the compute size back down.

What tool would you use to assess workload readiness for a migration to Azure SQL Database?

The Data Migration Assistant is a tool that can assess workload readiness for a migration to Azure SQL Database. It identifies potential issues that might impact the quality of your database before the migration begins.

Can the Azure SQL Migration Service handle migrations from multiple source databases to a single target database concurrently?

No, the Azure SQL Migration Service only supports one migration at a time from a source database to a targeted database.

If a migration fails, does the Azure Database Migration Service roll back the changes that were already migrated?

No, the Azure Database Migration Service does not provide a rollback feature for migrated data. You would have to handle this manually if rollback is needed.

Can you pause a migration activity in the Azure Database Migration Service?

No, once a migration activity begins, it cannot be paused. The activity will run until it completes, fails, or is manually stopped.

How can you deal with incompatibility issues during migration?

To deal with incompatibility issues during migration, use the Data Migration Assistant. It performs an assessment, pointing out any incompatibility issues between the source and target servers and suggesting how to fix them.

What will happen if the target database exists during the migration?

If the target database exists during SQL Server to Azure SQL Database migration, the Data Migration Assistant will fail the migration. You have to ensure that the target database does not exist before starting the migration.

What should you do if you encounter a firewall issue during the migration?

If you encounter a firewall issue, check and ensure that your client machine’s IP address is added to the target SQL Server firewall’s allow list. Also, ensure that your SQL Server’s firewall is configured to allow Azure services.

Can you conduct a dry run of the migration process?

Yes, using the Azure Database Migration Service, you can perform a test migration. This verifies that everything works as expected before doing the actual migration.

Does the Azure Database Migration Service support migration from a SQL Server stored in Azure VM to Azure SQL Database?

Yes, the Azure Database Migration Service supports migration from SQL Server stored in an Azure virtual machine to Azure SQL Database.