Evaluate HADR for hybrid deployments
In this tutorial we will learn about how to Evaluate HADR for hybrid deployments.
Hybrid IT: Disaster recovery solutions
You can have a disaster recovery solution for your SQL Server databases in a hybrid IT environment by using availability groups, database mirroring, log shipping, and backup and restore with Azure Blob storage.
Availability groups
- Some availability replicas running in Azure VMs and other replicas running on-premises for cross-site disaster recovery. However, the production site can be either on-premises or in an Azure datacenter. Because all availability replicas must be in the same failover cluster, the cluster must span both networks (a multi-subnet failover cluster).
- Secondly, this configuration requires a VPN connection between Azure and the on-premises network.
- Further, for successful disaster recovery of your databases, you should also install a replica domain controller at the disaster recovery site.
Database mirroring
- One partner running in an Azure VM and the other running on-premises for cross-site disaster recovery by using server certificates. However, partners don’t need to be in the same Active Directory domain, and no VPN connection is required.
Further, another database mirroring scenario involves one partner running in an Azure VM and the other running on-premises in the same Active Directory domain for cross-site disaster recovery. A VPN connection between the Azure virtual network and the on-premises network is required. - Lastly, for successful disaster recovery of your databases, you should also install a replica domain controller at the disaster recovery site. SQL Server database mirroring is not supported for SQL Server 2008 or SQL Server 2008 R2 on an Azure VM.
Log shipping
- One server running in an Azure VM and the other running on-premises for cross-site disaster recovery. However, Log shipping depends on Windows file sharing. So a VPN connection between the Azure virtual network and the on-premises network is necessary.
- Further, for successful disaster recovery of your databases, you should also install a replica domain controller at the disaster recovery site.
Backup and restore with Azure Blob storage
On-premises production databases backed up directly to Azure Blob storage for disaster recovery.
Replicate and fail over SQL Server to Azure with Azure Site Recovery
On-premises production SQL Server instance replicated directly to Azure Storage for disaster recovery.
Free DR replica in Azure
If you have Software Assurance, you can implement hybrid disaster recovery (DR) plans with SQL Server without incurring additional licensing costs for the passive disaster recovery instance.
For example, you can have two free passive secondaries when all three replicas are hosted in Azure:
Firstly, two free passives when everything in Azure
- Secondly, you can configure a hybrid failover environment, with a licensed primary on-premises, one free passive for HA, one free passive for DR on-premises, and one free passive for DR in Azure:
- Lastly, to enable this benefit, go to your SQL Server virtual machine resource. Select Configure under Settings, and then choose the Disaster Recovery option under SQL Server License. Select the check box to confirm that this SQL Server VM will be used as a passive replica. And then select Apply to save your settings.
Reference: Microsoft Documentation