“Restore On-prem SQL DB to Azure SQL MI without Corrupting Pages: A Guide”
How to Prevent Page Corruption Scenarios While Restoring SQL DB Backup From On-Prem to Azure SQL MI
Introduction
The migration of large volumes of data and applications to the cloud can be a complex process, and it is important to understand the risks and implications of the move. When migrating a SQL Database from on-premises to Azure SQL Managed Instance, it is critical to be aware of the potential for page corruption during the restoration process. This article will discuss the potential for page corruption and the steps you can take to prevent it.
What is Page Corruption?
Page corruption occurs when a database page is read from storage and the data within it is found to be inconsistent or incomplete. This can happen due to a variety of reasons, such as hardware or software failure, or due to a change in the database structure that was not properly handled. In a SQL Server database, page corruption can lead to data loss or data inconsistency issues.
What Causes Page Corruption?
Page corruption can occur when a database page is read from storage and the data within it is found to be inconsistent or incomplete. This can happen due to a variety of reasons, such as hardware or software failure, or due to a change in the database structure that was not properly handled. In a SQL Server database, page corruption can lead to data loss or data inconsistency issues.
How to Prevent Page Corruption During a Migration
When migrating a SQL Database from on-premises to Azure SQL Managed Instance, there are several steps you can take to reduce the chances of encountering page corruption.
Verify Your Backups Before Migration
The first step is to verify the integrity of your backups before beginning the migration process. This can be done using the DBCC CHECKDB command, which will scan the database and report any errors. It is recommended to run this command before and after the migration to ensure the data is free of corruption.
Choose an Optimal Migration Path
The next step is to select an optimal migration path. When restoring a SQL Server database to Azure SQL Managed Instance, it is important to select a compatible migration path. For example, if you are restoring a SQL Server 2012 database, you should ensure that the target instance is running the same version of SQL Server.
Enable Page Checksums
In addition to verifying your backups and selecting an optimal migration path, it is also recommended to enable page checksums on the source and target instances. This will enable the server to detect any page corruption during the migration process and prevent the data from being corrupted.
Test Your Migrated Database
Once the migration is complete, it is important to test the migrated database to ensure that all of the data is intact and that there are no errors. It is recommended to run a DBCC CHECKDB command once again to check for any potential corruption.
Conclusion
Migrating a SQL Database from on-premises to Azure SQL Managed Instance can be a complex process, and it is important to understand the risks and implications of the move. Page corruption is a common problem when restoring databases, and it is important to take the necessary steps to prevent it. By verifying your backups, choosing an optimal migration path, enabling page checksums, and testing your migrated database, you can ensure that the data is correctly restored and that there are no page corruption issues.
References:
How to prevent Page corruption scenarios while restoring SQL DB backup from On-prem to Azure SQL MI
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1. Azure SQL MI Backup Restoration
2. On-Prem to Azure SQL MI