Azure Backup – Workload integration layer – Backup Extension

In Azure, the Workload Integration Layer and the Backup Extension are essential components of Azure Backup that facilitate the protection of more complex workloads and applications.

These workloads include Azure Virtual Machines (VMs), databases (e.g., SQL Server, Oracle), and file systems that may require application-consistent backups, granularity in backup, and the ability to perform application-level restores.

The Backup Extension plays a crucial role in integrating Azure Backup with these workloads, ensuring that backups capture both the application data and system data in a consistent manner.

Here’s a detailed breakdown of the Workload Integration Layer and Backup Extension in Azure Backup.

Workload Integration Layer in Azure Backup

The Workload Integration Layer refers to the architecture and services in Azure Backup that ensure smooth integration with various workloads (applications or services) running on Azure Virtual Machines, whether on the Azure platform or on-premises.

This layer manages the backup and recovery of workloads that require specific handling due to their complexity, such as databases or custom applications.

Azure Backup provides specialized support for workloads that need application-consistent backups, which are critical for ensuring that backup copies of data, such as databases, are in a valid and recoverable state when restored.

This requires additional integration mechanisms, typically through Backup Extensions.

Key Workloads Supported

1. Azure VMs: These include both Windows and Linux VMs.

2. SQL Server: Both SQL Server on Azure VMs and Azure SQL Database can be backed up using the Workload Integration Layer.

3. Oracle Databases: For Oracle DBs running on Azure VMs, application-consistent backups are enabled.

4. Azure Files: For file share backups, especially when additional integration with applications is required.

5. Custom Workloads: Azure Backup can integrate with other custom applications through the Backup Extension to provide application-consistent backups.

The integration layer simplifies the process of backing up complex workloads in Azure, handling their unique backup requirements, and ensuring the data is backed up consistently.

Backup Extension in Azure Backup

The Backup Extension is a key component in the Azure Backup architecture that enables the backup of specific workloads.

It acts as the bridge between the Azure Backup infrastructure and the workload (e.g., VMs, databases, applications).

It works with Azure Backup to manage the backup process by interacting with the operating system or application layer of the virtual machine or server to facilitate application-consistent backups.

In simpler terms, the Backup Extension enables Azure Backup to recognize, understand, and protect workloads that require special backup handling, like database services and other critical applications.

How Backup Extensions Work

1. Installation: The Backup Extension is installed on the virtual machine or server that you want to back up. It integrates into the system and allows Azure Backup to communicate with the operating system and installed applications (e.g., SQL Server, SharePoint) to perform application-consistent backups.

2. Communication with Azure Backup: The Backup Extension communicates with the Recovery Services Vault and triggers backup jobs based on the defined backup policies. This communication includes sending backup requests and information about the VM’s status.

3. Pre-backup and Post-backup Scripts: The Backup Extension can interact with the workload’s own mechanisms for quiescing and ensuring that the application is in a consistent state before the backup starts, and it can run scripts after backup is completed.

   • For example, for SQL Server, the Backup Extension ensures that database transactions are safely backed up and that the backup is application-consistent.

   • Similarly, for Oracle, the Backup Extension ensures that database logs and data files are captured correctly during the backup process.

4. Application-Consistent Backups: The extension ensures that backups of applications are application-consistent by:

   • Quiescing the application (e.g., pausing transactions or flushing transaction logs).

   • Taking a snapshot of the application data while the application is in a consistent state.

   • Allowing for point-in-time restore of the application with minimal risk of data loss.

Types of Backup Extensions

1. Azure Backup VM Extension: For backing up entire Azure Virtual Machines, including their operating system and data disks. This is applicable for both Windows and Linux VMs.

   • Windows: The extension enables volume shadow copy service (VSS), which ensures application-consistent backups for Windows-based workloads.

   • Linux: The extension works with FSFreeze or other mechanisms to ensure application consistency in Linux environments.

2. Azure Backup for SQL Server: Azure Backup can back up SQL Server databases running on Azure VMs or on-premises. The extension ensures that backups are application-consistent by integrating with SQL Server's VSS Writer.

3. Azure Backup for SAP HANA and Oracle: Backup extensions for Oracle and SAP HANA allow integration with these complex applications for consistent and reliable backups. These backups are also application-consistent, ensuring that Oracle's data files, logs, and control files are properly captured.

4. Custom Backup Extensions: Some custom applications require specialized backup processes. For example, custom scripts or agents might be used to ensure backups of certain business-critical applications.

Application-Consistent Backups with Backup Extensions

An application-consistent backup is critical for certain workloads (especially databases), where it’s essential to ensure that data is consistent and in a valid state when restored.

Without application consistency, there’s a risk of data corruption or loss when the application is restored.

The Backup Extension ensures that application-consistent backups are created by managing the application's state during the backup process.

Here’s how it works:

1. Quiescing the Application: Before the backup, the extension ensures that the application is in a stable state, which may include pausing certain processes or flushing in-memory data to disk. For example, SQL Server might pause transaction logs to ensure no data is in-flight during the backup.

2. Backup of Application Data: The Backup Extension interacts with the application to capture its data in a consistent manner. This could involve VSS for Windows-based systems or custom methods for other workloads like Oracle.

3. Restore with Application Consistency: When restoring the backup, the extension ensures that the application is restored to its exact state at the time of the backup, with no risk of partial transactions or data loss.

Application Examples

1. SQL Server: The Azure Backup extension integrates with SQL VSS Writer to perform application-consistent backups, including the transaction logs and database data.

2. Oracle: The backup extension ensures that all relevant data files, control files, and logs are backed up in a consistent state.

3. SharePoint: The extension handles application-consistent backups by ensuring the databases are backed up in a consistent state and that SharePoint services are properly quiesced.

Benefits of Using Backup Extensions

1. Application Consistency: By enabling Azure Backup to interact with applications directly, backup extensions ensure that the backup captures application data in a consistent state, allowing for reliable and consistent restores.

2. Granular Backup and Restore: Backup extensions allow for more granular backup options, such as backing up individual workloads (SQL databases, Oracle, etc.) or specific parts of an application while excluding others.

3. Simplified Management: Azure Backup with workload integration (via extensions) simplifies the management of complex backup jobs, ensuring that application-specific backup needs are met without requiring manual intervention or third-party tools.

4. Seamless Integration with Azure: The extension seamlessly integrates with Azure Backup's Recovery Services Vault, ensuring centralized management and monitoring for all backups.

5. Minimal Impact on Applications: The Backup Extension uses application-aware methods to minimize downtime or impact on running applications during the backup process. This ensures that business operations are not disrupted.

How to Deploy Backup Extensions

The process of deploying the Backup Extension is relatively straightforward:

For Azure VMs

1. When you enable backup for a VM in the Azure Portal, the Backup Extension is automatically deployed to the VM.

2. This extension is installed as part of the Azure VM backup configuration process.

3. Azure handles the deployment and update of the extension to ensure that backups can be performed properly.

For SQL Server and Other Workloads

1. If you're backing up specific applications, such as SQL Server, you will need to configure the extension by enabling SQL Server backup under the Backup settings.

2. In some cases, additional configuration might be required, such as ensuring that the VSS writer is installed and functioning correctly.

For On-Premises Machines

1. For on-premises workloads, the extension must be manually installed on the machine. You can use the Azure Backup Agent or Azure Backup Server to install the necessary backup extensions for protecting specific workloads.

Summary

The Backup Extension is an essential component of Azure Backup's Workload Integration Layer, allowing for application-consistent backups of complex workloads such as virtual machines, SQL Server, Oracle databases, and more.

By integrating with the application layer, Backup Extensions ensure that your backups are consistent, reliable, and easily restorable.

This functionality is crucial for ensuring the integrity and recoverability of critical applications and their data in the event of a disaster.