Evaluate Azure-specific HA/DR solutions

Azure provides several high availability (HA) and disaster recovery (DR) solutions for Microsoft Azure SQL solutions. These solutions are essential to ensure the availability, reliability, and business continuity of your SQL databases. In this article, we will evaluate some Azure-specific HA/DR solutions that are relevant to the “Administering Microsoft Azure SQL Solutions” exam.

1. Azure Availability Zones

Azure Availability Zones are physically separate data centers within an Azure region. They provide redundant power, cooling, and networking, ensuring high availability for your applications and databases. By deploying your Azure SQL databases in different availability zones, you can achieve excellent HA for your solutions. Azure platform takes care of routing and failover between these zones, reducing the impact of hardware or software failures.

To create an Azure SQL database in an availability zone, you can use the following Azure CLI command:

az sql db create --name --resource-group --server --zone-redundant

2. Geo-replication

Azure SQL offers built-in geo-replication to provide disaster recovery capabilities. Geo-replication asynchronously replicates your primary database to a secondary database in a different Azure region. This ensures that your database remains available even in the event of a catastrophic failure in the primary region. You can read from the secondary database, but writes are only allowed to the primary.

To configure geo-replication for an Azure SQL database, you can follow the steps outlined in the Azure portal or use the PowerShell command:

New-AzSqlDatabaseSecondary -ResourceGroupName -ServerName -DatabaseName -PartnerResourceGroupName -PartnerServerName -AllowConnections "All"

3. Azure SQL Managed Instance

Azure SQL Managed Instance is a fully managed database service that provides native HA and DR capabilities. Managed Instance automatically replicates your database within the same Azure region to ensure high availability. It also supports read replicas that can be used for scaling out read workloads and providing additional redundancy.

To create a Managed Instance with HA, you can use the Azure portal or Azure CLI command:

az sql mi create --name --resource-group --location --high-availability true

4. Backup and Restore

Regular backups are crucial for disaster recovery. Azure SQL provides automated backups for its databases. These backups are stored in Azure Blob Storage and can be restored to the same or different Azure SQL server. You can also configure long-term retention for backups, which allows you to restore databases to any point in time within the retention period.

To configure long-term retention using T-SQL, you can execute the following command:

ALTER DATABASE [] SET LONG_TERM_RETENTION_POLICY TO ;

5. Azure Site Recovery

Azure Site Recovery (ASR) is a comprehensive DR solution for Azure services. It helps you replicate and failover your entire Azure environment, including Azure SQL databases, to a secondary region. ASR provides near-zero downtime during failover and allows for quick recovery in case of a disaster.

To configure ASR for Azure SQL databases, you can follow the step-by-step guide provided in the Azure Site Recovery documentation.

In conclusion, Azure offers various HA/DR solutions for Microsoft Azure SQL solutions. These solutions provide different levels of redundancy, failover capabilities, and disaster recovery options. Understanding and implementing these solutions is essential for administering Azure SQL databases effectively.