Azure SQL Database Planning

Introduction to Planning Azure SQL Database

Effectively planning your Azure SQL Database deployment is crucial for ensuring optimal performance, cost-efficiency, and reliability. This guide outlines key considerations and best practices to help you make informed decisions.

Azure SQL Database offers a fully managed Platform as a Service (PaaS) database engine that handles most database management functions without requiring user involvement, including upgrading, patching, and backups. However, strategic planning is still essential.

Sizing and Performance

Choosing the right compute and storage resources directly impacts performance and cost. Azure SQL Database offers two primary purchasing models and various service tiers.

DTU (Database Transaction Unit) Model

The DTU model provides a simple, bundled measure of database throughput based on a blended measure of CPU, memory, and I/O resources. It's ideal for predictable workloads.

  • Basic: Entry-level for small, less demanding workloads.
  • Standard: A balanced option for most common applications.
  • Premium: For high-performance, mission-critical workloads requiring guaranteed resources and faster I/O.

vCore (Virtual Core) Model

The vCore model offers more granular control over resources and is often more cost-effective for independent databases. You can choose compute tier (Provisioned or Serverless) and hardware generation.

  • General Purpose: Balanced compute and storage for most business workloads.
  • Business Critical: For mission-critical applications with highest performance and availability requirements.
  • Hyperscale: For very large databases (up to 100TB) with rapid scaling needs.

Performance Tiers (vCore Model)

Within the vCore model, you select a performance tier based on your application's needs:

  • Provisioned Compute: You provision a specific amount of compute resources for a predictable cost.
  • Serverless Compute: Automatically scales compute based on workload demand and pauses inactive databases, offering cost savings for intermittent workloads.

Storage Considerations

When planning storage, consider:

  • Maximum Storage Size: Ensure sufficient space for your data, logs, and backups.
  • I/O Throughput and IOPS: Higher tiers and Premium/Business Critical levels offer better I/O performance.
  • Storage Costs: Storage is billed separately from compute in the vCore model.

Deployment Options

Azure offers several ways to deploy and manage SQL Server databases.

Single Database

A fully managed relational database with its own set of resources managed via DTUs or vCores. Ideal for new cloud applications or migrating individual databases.

Elastic Pools

A cost-effective solution for managing and scaling multiple databases with varying and unpredictable usage demands. Resources are shared among databases in the pool.

Azure SQL Managed Instance

A fully managed SQL Server instance hosted in Azure. It offers near 100% compatibility with on-premises SQL Server, making it ideal for lift-and-shift migrations of existing applications that require instance-level features.

SQL Server on Azure Virtual Machines

For maximum control and compatibility, you can run SQL Server on Azure Virtual Machines. This provides the most flexibility but requires managing the OS and SQL Server software yourself.

High Availability and Disaster Recovery

Azure SQL Database offers robust features to ensure your data is always available and protected.

Availability Options

Service tiers come with different built-in availability SLAs:

  • Basic/Standard: Local redundancy.
  • Premium/General Purpose (Provisioned): Zone-redundant configurations for higher availability.
  • Business Critical: Built-in always-on availability groups for high availability and fast failover.

Geo-Replication

Configure readable secondary databases in different Azure regions for disaster recovery. Failover can be manual or automatic.

Backups

Azure SQL Database automatically performs full, differential, and transaction log backups. You can configure retention policies and restore to any point in time within the retention period. Long-term backup retention is available.

Security Best Practices

Securing your data in Azure SQL Database is paramount.

Network Security

  • Configure firewall rules to restrict access to authorized IP addresses.
  • Use virtual network service endpoints or private endpoints for secure network access.

Authentication

  • Prefer Azure Active Directory authentication over SQL authentication for centralized identity management.
  • Implement the principle of least privilege for user and application access.

Data Encryption

  • Transparent Data Encryption (TDE) is enabled by default to encrypt data at rest.
  • Consider Always Encrypted for sensitive data that requires protection even from database administrators.
  • Use Dynamic Data Masking to obfuscate sensitive data for non-privileged users.

Cost Management

Monitor and optimize your Azure SQL Database costs by:

  • Choosing the appropriate purchasing model (DTU vs. vCore) and service tier.
  • Leveraging Serverless compute for intermittent workloads.
  • Utilizing Azure Hybrid Benefit for existing SQL Server licenses.
  • Right-sizing your resources based on actual usage.
  • Implementing auto-pause for Serverless databases.
  • Monitoring costs using Azure Cost Management + Billing.

Regularly reviewing your database performance and resource utilization will help you identify opportunities for cost savings.