Azure SQL Database and Managed Instance

Azure SQL Database is a fully managed cloud database service known for its scalability and ease of management. This Platform-as-a-Service (PaaS) offering includes high availability, automated backups, and comprehensive maintenance operations, allowing users to focus on their applications rather than infrastructure management. This Microsoft Azure database is suitable for developers and businesses that prefer to avoid investing heavily in hardware and software management while still needing robust database capabilities.

Part of the Azure SQL family, SQL Managed Instance is an intelligent cloud database service combining the broadest SQL Server engine compatibility (back to SQL Server 2008) with the benefits of a fully managed, up-to-date platform as a service.

Managed Instance provides a cloud environment that mirrors SQL Server, offering high compatibility with SQL Server features. It is an optimal choice for businesses aiming to migrate their SQL Server databases to the cloud with minimal architectural changes. Managed Instance combines the luxury of managed service with flexibility and SQL Server feature compatibility, which is highly beneficial for those looking to leverage cloud scalability while maintaining familiarity with SQL Server environments.

Migrating existing SQL databases to Azure SQL DB or Managed Instance is relatively straightforward with tools like Azure Database Migration Service, which provides guided migration processes. This service helps assess, migrate, and optimize database workloads to Azure SQL DB or Managed Instance, ensuring a seamless migration experience. It’s particularly beneficial for moving large databases and maintaining data integrity during the transition.

Before migrating to Azure SQL DB or Managed Instance, organizations should:

• Assess: Utilize tools like the Data Migration Assistant to check for compatibility issues.
• Plan: Decide on the Azure SQL service and pricing tier that align with your workload requirements and to help determine your Azure migrate cost.
• Prepare: Align your data with Azure’s security and compliance capabilities.
• Strategize: Create a detailed migration plan, including test migrations and contingency procedures.

Microsoft recommends several tools for migrating to Azure SQL DB: Azure Migrate, Data Migration Assistant, and Azure Database Migration Service. These tools support various migration scenarios, including transaction replication, Import Export Service/BACPAC, and Bulk copy. They are designed to streamline the migration process, offering assessment, migration, and post-migration optimization capabilities. Each tool caters to different migration requirements, ensuring users can choose the one that best fits their specific use case and technical environment.

Managed Instance closely aligns with on-premises SQL Server, offering near-complete feature parity and enabling easy migration of SQL Server applications to the cloud without code changes. It’s designed for predictable performance and environmental control, crucial for mission-critical workloads. The native virtual network ensures isolated and secure database environments.

Performance in Managed Instance is tailored to the selected service tier, addressing various workload requirements. The General Purpose tier suits standard business applications with typical I/O demands. Meanwhile, the Business Critical tier is geared towards high-performance applications, featuring faster compute, higher I/O throughput, and in-memory technologies like In-Memory OLTP for demanding workloads. Recent updates have introduced doubled max log rate for the Business Critical tier and support for new features like fast provisioning and improved network security.

Pricing for Azure SQL DB and Managed Instance is based on factors including service tier, compute resources (vCore), and storage.

• Azure SQL DB offers flexibility with options like serverless compute, which can help optimize costs by automatically scaling compute resources and billing only for the resources used.
• Managed Instance pricing is generally based on the chosen tier and allocated resources suitable for predictable workloads. Both services offer pricing models to cater to various business needs and workload requirements.

Azure SQL Managed Instance has two main service tiers: General Purpose and Business Critical. The General Purpose tier uses Azure Premium Storage, suitable for applications with standard performance and I/O latency needs. It provides a cost-effective solution for various workloads. The Business Critical tier employs local SSD storage for higher performance requirements, offering features like in-memory OLTP and additional read-only replicas. Storage limits and I/O throughput scale with the provisioned database compute resources, allowing for effective performance and cost balance in both tiers.

For Azure SQL DB, tools like SQL Database Advisor and Performance Insights help identify performance bottlenecks and provide recommendations for optimization.

With a Managed Instance, performance tuning can involve adjusting resource allocations, indexing strategies, and query tuning. Both services offer extensive monitoring capabilities through Azure Monitor and Azure SQL Analytics, providing insights into performance metrics and trends.

Azure SQL DB and Managed Instance prioritize security and include advanced features like network security, encryption, threat detection, and identity management.

• Azure SQL DB: This service leverages Azure’s robust security infrastructure, providing essential capabilities like Transparent Data Encryption for protecting data at rest, SQL auditing for tracking database activities, and Entra ID (formerly Azure AD) authentication for secure identity management. Recent updates have introduced features like Always Encrypted with VBS enclaves, which enhance data security by allowing confidential queries and in-place encryption operations without exposing sensitive data.
• Azure SQL Managed Instance: In addition to the common security features shared with Azure SQL DB, Managed Instance offers additional controls for managing instance-level security settings. This is especially beneficial for applications requiring a higher degree of control over security. Managed Instance’s updates include improved network security features and the ability to link to SQL Server 2022, further enhancing its security posture and compliance capabilities.

High availability and disaster recovery are key strengths of both Azure SQL DB and Managed Instance as component of Azure SQL Database Backup. Azure SQL DB offers built-in high availability with a 99.99% availability SLA and features like automated backups and zone-redundant databases. Managed Instance has been augmented with zone-redundancy, enhancing its disaster recovery capabilities and providing additional resiliency against regional outages. This update strengthens data protection and ensures business continuity, aligning with the high availability provided by SQL Server Always On technology.

Azure SQL DB provides up to 35 days of PITR for backups. This feature allows you to restore your database to any point within that time-period and recover from accidental data changes or loss. PITR is a crucial aspect of data protection and disaster recovery, as it enables quick recovery to a known good state following user errors, application errors, or malicious activities. Azure automates the backup process and ensures that the backups are maintained and available for the specified retention period, offering peace of mind and operational reliability.

Accelerated Database Recovery (ADR) is a revolutionary feature that enhances the database engine’s recovery process. It significantly improves database availability, particularly for long-running transactions, by providing instantaneous transaction rollback and faster, consistent database recovery. This feature is especially beneficial in scenarios involving complex transactions and large databases, as it minimizes the time for recovery operations. By default, ADR is enabled, ensuring users benefit from reduced downtime and enhanced performance during database recovery operations.

Managed Instance fully supports SQL Server Agent, a significant benefit for organizations moving from on-premises SQL Server environments to the cloud. This support ensures that essential scheduled tasks such as database backups, maintenance tasks, data imports/exports, and other routine jobs can be seamlessly migrated and managed in the cloud. The SQL Server Agent in Managed Instance offers familiar features, including job scheduling, alerts, and operators, making it an indispensable tool for database administrators. Its inclusion simplifies the automation of tasks and aligns closely with the operational practices established in on-premises environments.

Azure SQL DB offers a unique feature in its serverless model that allows pausing the compute resources when the database is inactive. This feature helps save costs as you only pay for the storage during the paused state, making it an efficient choice for workloads with intermittent usage patterns. Azure SQL Managed Instance has recently introduced a similar feature, currently in preview, allowing the stopping and starting of compute resources. This feature is particularly beneficial for development and testing environments where the Instance does not need to run continuously, thus providing significant cost savings and operational flexibility.