[Edit: Apr. 28 2023]: The feature is now Generally Available (GA). For more information, see Managed Instance link doc pages.
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In the previous article Managed Instance link – connecting SQL Server to Azure reimagined, we've introduced the link feature for Azure SQL Managed Instance as our best hybrid solution for Managed Instance, allowing near real-time data replication from SQL Server to Managed Instance using the proven Always On technology.
As of today, we are pleased to announce that the link feature for Managed Instance is available in the open public preview, in all Azure regions worldwide. It can be used with existing, or new managed instances, and SQL Server 2019 Enterprise, or Developer edition, including SQL Server 2022 CTP (available through EAP). We have also released the tooling support for the link in the form of automated wizards available in SQL Server Management Studio, starting from SSMS v18.11.1.
With the link, replicated databases from SQL Server on Managed Instance are usable as R/O secondary replicas. While the link is in operation, transactions committed on SQL Server (primary) are instantaneously committed to Managed Instance (secondary). This provides an exact replica of your SQL Server database on Managed Instance, synced near real-time. The default link replication mode is asynchronous, with an option to switch the replication mode to synchronous on-demand. The link was built to be resilient, in case of the network being down, SQL Server being rebooted, or maintained, or in case of some other issue, the link will automatically resume replicating where it has left off when the issue has been resolved. The link is also secure as VPN or Express Route (Azure's premium VPN) is used to connect SQL Server to Managed Instance via a private endpoint. Data transmitted over the wire is encrypted, and we also support replication of TDE encrypted databases providing an additional layer of security.
We understood your needs to remain running SQL Server on-premises, in your own data centers, or hosted in a VM anywhere, while needing to use your SQL Server data with a vast range of Azure services, such are analytics, Synapse, or ML, for example. MI link has addressed this need by allowing you to immerse in Azure at your own pace, as you could be running the link without any time limitations, for weeks and months at a time, and without having to migrate to Azure. Some of our customers are using the link to offload reporting, analytics and ETL workloads to Managed Instance, or using the link to scale R/O application workloads on Managed Instance. De-risk migrations by using the replicated data in Azure to test your production R/O workloads prior to migrating. When and if you are ready to migrate to Azure, use the link as our best minimum downtime migration solution for migrating your SQL Server workloads to Azure, compared to all of our other products available today for Managed Instance.
When to use the link
Use the link to support one of the following scenarios:
- Scale R/O workloads, analytics, ETL and similar workloads from SQL Server to Managed Instance (i.e. use Managed Instance as a readable secondary replica)
- Consolidate and deconsolidate SQL Server workloads on Managed Instance
- Complete minimum downtime migration (one way) from SQL Server to Managed Instance
To learn more and see a demo of the link in action, register for Azure webinar Connect Your SQL Server to Azure SQL Managed Instance. After the registration, you will receive an email with a link to the recorded webinar.
Getting started
To start using managed instance link, you will need to have the following available:
- SQL Server 2019 Enterprise Edition or Developer Edition with CU15 (or above), or SQL Server 2022 CTP (available through EAP) installed on-premises, or on an Azure VM.
- Network connectivity between your SQL Server and managed instance is required.
- If your SQL Server is running on-premises, use a VPN link or Express route.
- If your SQL Server is running on an Azure VM, deploy your VM to the same VNet as your managed instance, or
- If your Azure VM is in a different VNet, use global VNet peering to connect the two.
- Azure SQL Managed Instance provisioned in any service tier.
Create the link
To help with the initial environment setup, we have prepared the following online guide on how to setup your SQL Server environment to use with the link feature for Managed Instance:
Once you have ensured the pre-requirements have been met, you can create the link using the automated wizard in SSMS, or you can choose to setup the link manually using scripts. Create the link using one of the following instructions:
- Replicate database with Azure SQL Managed Instance link feature in SSMS, or alternatively
- Replicate database with Azure SQL Managed Instance link feature with T-SQL and PowerShell scripts
Once the link has been created, ensure that you follow the best practices for maintaining the link, by following instructions described at this page:
Minimum downtime migration to Azure
If and when you are ready to migrate a database to Azure with a minimum downtime, you can do this using an automated wizard in SSMS, or you can choose to do this manually with scripts. Migrate database to Azure link using one of the following instructions:
- Failover database with link feature in SSMS, or alternatively
- Failover (migrate) database with Azure SQL Managed Instance link feature with T-SQL and PowerShell scripts
Roadmap
Our aim is to provide support for SQL Server versions 2016 and above (2016, 2017, 2019 and 2022). Please note that support for earlier SQL Server versions (2008, 2012 and 2014) is not possible as engines of these products lack required Always On capability for our feature. In addition, our aim is to also build bi-directional disaster recovery (DR) on Azure SQL Managed Instance exclusively for SQL Server 2022.
If you're interested in using Link feature for Azure SQL Managed Instance with SQL Server versions and editions that are currently not supported (2016, 2017, standard editions, DR for 2022), sign-up for the managed instance link EAP (Early Access Program) for future consideration by the product group:
Closing remarks
As our products continuously evolve, please note that features and options presented in this article are subject to change. This article reflects the state of the link feature options available for Managed Instance in March, 2022.
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