Understanding Azure SQL and Its Backup Mechanisms

3 min read
Cloud Platforms › Azure
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Azure SQL is a family of managed, cloud-based database services offered by Microsoft, built on the SQL Server engine. It provides organizations with the flexibility to deploy and manage databases in the cloud without the overhead of maintaining physical infrastructure. This article explores Azure SQL’s different deployment options and explains its backup mechanisms.

Overview of Azure SQL Deployment Options

Azure SQL consists of three primary deployment models, each catering to different requirements:

SQL Server on Azure Virtual Machines (VMs) (Infrastructure as a Service - IaaS)

  • This option allows users to run a full SQL Server instance on an Azure VM.
  • It provides complete control over the operating system and database environment.
  • Best suited for organizations that require OS-level access and minimal changes when migrating existing SQL workloads to the cloud.

Azure SQL Managed Instance (Platform as a Service - PaaS)

  • A fully managed database service that reduces the administrative burden of managing virtual machines.
  • Ideal for applications requiring instance-scoped features like SQL Server Agent and linked servers.
  • Removes the need for direct OS access but still provides a near-full SQL Server experience.

Azure SQL Database (Platform as a Service - PaaS)

  • A cloud-native, fully managed database service optimized for modern applications.
  • Supports features like serverless compute and hyperscale storage for dynamic scalability.
  • Best suited for new cloud applications that require a highly available and managed database solution.

Backup Mechanisms in Azure SQL

Azure SQL provides automated and configurable backup options to ensure data protection and recoverability. The backup strategy varies depending on the deployment model.

Automated Backups for Azure SQL Database and Managed Instance

For Azure SQL Database and Managed Instance, Microsoft automatically manages backups with the following approach:

  • Full Backups: Taken weekly and provide a complete snapshot of the database.
  • Differential Backups: Captured every 12-24 hours to record changes since the last full backup.
  • Transaction Log Backups: Performed approximately every 10 minutes, enabling point-in-time recovery (PITR).

These backups are stored in geo-redundant storage, ensuring resilience even in case of regional failures. By default, point-in-time restore backups are retained for 7 to 35 days, depending on the service tier.

Long-Term Retention (LTR) Backups

For compliance and archival purposes, Azure SQL supports Long-Term Retention (LTR) of backups:

  • Allows storing backups for up to 10 years.
  • Configured to store weekly, monthly, or yearly backups in separate blob storage.
  • Enables restoration of historical backups as new databases.

Backup Options for SQL Server on Azure VMs

Unlike fully managed services, SQL Server on Azure VMs requires a more manual backup approach. Users can manage backups using:

  • Native SQL Server tools (SQL Server Management Studio, Maintenance Plans, or Transact-SQL commands).
  • Azure Backup for SQL Server: A cloud-based backup solution that provides centralized management, long-term retention, and automated scheduling.

Azure Backup for SQL Server offers advantages such as zero-infrastructure backup and automatic policy enforcement across multiple VMs.

Conclusion

Azure SQL provides a range of deployment options tailored to different needs, along with robust backup and recovery mechanisms. While Azure SQL Database and Managed Instance benefit from fully automated backups, SQL Server on Azure VMs requires a more hands-on approach. Understanding these options helps organizations choose the right Azure SQL solution while ensuring data protection and disaster recovery readiness.