Know what data in Azure is backed up and how

Azure provides a comprehensive set of backup solutions to ensure the protection and availability of various types of data within the platform.

The data that can be backed up in Azure typically falls under several categories, including Virtual Machines (VMs), SQL databases, Azure Files, Azure Blob Storage, and Application Data.

Each of these data types requires different backup methods and strategies, depending on the specific Azure service.

Let’s explore what data can be backed up in Azure, and the mechanisms or tools used to back it up.

Virtual Machines (VMs)

Azure offers native backup services to back up entire Virtual Machines (VMs), including the operating system and data disks.

How VM Backups Work

Azure Backup is the primary service for backing up Azure VMs.

It integrates with Recovery Services Vaults to store backup data.

Backup Process

1. Snapshot-based Backup: Azure Backup takes a snapshot of the VM’s disks (OS and data disks) at a point in time, ensuring consistency.

2. Incremental Backups: After the initial backup, Azure Backup uses incremental backups to store only changes made since the last backup, reducing storage consumption and backup times.

3. Application-Consistent Backups: Azure Backup can capture application-consistent backups, especially for applications running on VMs (like SQL Server), ensuring that backups are consistent and restorable to a clean state.

VM Backup Components

1. OS Disk: The operating system disk of the VM.

2. Data Disks: Any attached data disks are also included in the backup.

3. Restore Options: You can restore the entire VM, specific disks, or perform file-level recovery using Azure File Recovery.

Backup Frequency

Azure Backup allows you to schedule backups at regular intervals, typically daily, with flexible retention policies.

Azure SQL Databases

Azure provides multiple options to back up SQL databases, including Azure SQL Database (PaaS) and SQL Server on Azure VMs.

How Azure SQL Database Backups Work

Automated Backups (PaaS)

1. Built-in Backups: Azure SQL Database has built-in automated backups that are automatically configured when the database is created.

2. Backup Frequency: Automated backups are taken every 24 hours, and transaction log backups are taken every 5-10 minutes, which ensures point-in-time restore capabilities.

3. Retention: You can retain backups for up to 35 days depending on the service tier. You can configure the long-term retention (LTR) of backups for compliance requirements.

Manual Backups

You can also take manual backups of the database using Azure SQL Database's Export functionality, which creates a BACPAC file stored in Azure Blob Storage.

This file can be used for migrating or restoring databases.

Azure VM with SQL Server

If you're using SQL Server on an Azure VM, you can back up the database using traditional SQL Server backup methods and store the backup in Azure Blob Storage.

Additionally, Azure Backup can be used to back up the entire VM, including SQL Server databases.

Azure Blob Storage

Azure Blob Storage is a highly scalable object storage service used for storing unstructured data, including documents, images, and backups.

How Blob Storage Backups Work

Azure Backup

Azure Backup supports backing up the contents of Azure Blob Storage by leveraging Azure Storage Snapshot technology.

1. Snapshot-based Backup: Snapshots capture the state of your blob storage container at a specific time, making it easy to restore to that point.

2. Soft Delete: Azure provides a soft delete feature for Blob Storage, where deleted blobs are retained for a specified period, allowing you to recover them.

Alternative Backup Solutions

1. Azure Storage Account replication (e.g., Geo-Redundant Storage (GRS)) can help to ensure high availability and resilience by maintaining copies of the data in a secondary region.

2. Azure Files: If you use Azure Files, it is possible to back up shares using Azure Backup.

Azure Files (File Shares)

Azure File Shares are managed file shares in the cloud that use the Server Message Block (SMB) protocol for access.

Backing up file shares is a critical feature for data protection.

How Azure File Share Backups Work

Azure Backup for Azure Files

1. Backup Solution: Azure Backup provides a built-in solution for backing up Azure Files, including SMB-based file shares.

2. Snapshot-based Backup: The service uses snapshots to back up the file share and retains backup copies in a Recovery Services Vault.

3. Scheduled Backups: You can schedule backups at specific intervals (e.g., daily or weekly) and set retention policies.

Restore Options

File-level restoration is possible.

You can restore entire file shares or specific files from a backup snapshot.

Granular Recovery:

Allows you to recover from different points in time, providing flexibility in case of accidental deletion or data corruption.

Azure Virtual Machines (VM) with Managed Disks

Managed disks in Azure are a better and simpler way to manage storage for Azure VMs.

They can be backed up just like traditional VMs.

How Managed Disks Backup Works

1. Azure Backup: Managed disks are backed up using the same Azure Backup technology that works for regular VMs.

2. Incremental Backups: Like regular VMs, backups of managed disks are incremental, so only changes after the previous backup are stored.

3. Snapshot-based Backup: A snapshot of the managed disk is created, and this snapshot can be used to restore the VM.

Azure Kubernetes Service (AKS)

Azure Kubernetes Service (AKS) enables the deployment, management, and scaling of containerized applications.

How AKS Backups Work

Backup Configuration

1. Persistent Volumes (PVs) in AKS can be backed up using Azure Backup for Azure Blob Storage or Azure Files.

2. Cluster Backup: To back up entire AKS clusters, you may need to back up container data stored in persistent volumes separately.

Backup Tools

1. Velero: An open-source tool often used with AKS for backing up Kubernetes resources (including PVs, namespaces, deployments, etc.) and to restore them when needed.

Azure Active Directory (Azure AD)

Azure Active Directory is a cloud-based identity and access management service.

While Azure AD itself does not require regular backup, certain configurations and data need to be protected.

How Azure AD Data is Protected

1. Azure AD Backup is not typically required because Azure AD uses a multi-tenant, distributed system for high availability and resilience.

2. Backup of User and Group Data: However, critical data like conditional access policies and group memberships can be exported periodically for protection.

3. Azure AD Connect: Azure AD Connect configurations (which sync on-premises directories to Azure AD) can be backed up manually by exporting the configuration.

Application Data and Other Azure Services

Some applications or services hosted in Azure require custom backup solutions:

How Application Data is Backed Up

1. Azure App Services: You can back up application data for Azure App Services using Azure Backup or manually by exporting configurations and storing them in Azure Blob Storage.

2. Azure Redis Cache: For Azure Redis, backups can be configured to export data at periodic intervals to Azure Blob Storage.

3. Azure Database for PostgreSQL, MySQL: Azure provides built-in backup solutions for databases like PostgreSQL and MySQL, similar to the solution for Azure SQL Database. These databases are backed up automatically on a scheduled basis, with retention of 7-35 days.

Summary

Azure provides comprehensive backup options for various types of data stored in its cloud environment.

Data can be backed up using Azure Backup, Azure Site Recovery, and native Azure services (such as Azure Blob Storage, Azure Files, Azure SQL Database, VMs, etc.).

The backup process typically includes snapshot-based backups, incremental backups, and application-consistent backups to ensure that the data is protected and can be recovered to a specific point in time.

By using these tools and solutions, businesses can ensure high availability and resilience of their applications, databases, and virtualized workloads in the cloud.