Amazon RDS Custom for SQL Server Is Now Generally Available


Amazon has announced general availability of Amazon RDS Custom for SQL Server. The new service supports legacy, custom, and packaged applications that depend on specific configurations and third-party tools, and which historically have not been able to move to a fully managed database.

Last October, Amazon introduced RDS Custom, a managed service for applications that need access to the underlying operating system and database environment. With the latest announcement from re: Invent, SQL Server is now the second database engine supported on RDS Custom, after Oracle. The new option is designed for SQL Server applications that depend on customizations of corporate environments and content management systems, such as Microsoft SharePoint.

Channy Yun, Senior Developer Advocate at AWS, explains how it works:

With RDS Custom for SQL Server, you can enable features that require elevated privileges like SQL Common Language Runtime (CLR), install specific drivers to enable heterogeneous linked servers, or have more than 100 databases per instance.


The new service accepts connections using AWS Systems Manager Session Manager or an RDP client. It includes the automation of backups and provides instance monitoring and recovery. Brent Ozar, SQL Server expert, tweets:

This is intriguing to the folks at SQL Server who wanted to migrate to AWS RDS and Azure SQL DB, but couldn’t because they wanted access to OS, CLR,> 100 databases per server, etc.

To apply customizations, administrators can pause the automation mode that performs backups and monitors the database, storage, and EC2 state. On SQLSailor, Anup Warrier, Senior Solutions Architect at AWS, explains why this is a “fresh start” for SQL Server on RDS:

As a user you never had access to the host operating system, you did not have SA access to the instance, you could not run CLR, and anything that required elevated privileges was prohibited . This is what is changing with RDS Custom for SQL Server. With RDS Custom, there is a notion of shared responsibility that is at stake now. You are now allowed to make custom changes to the database, access the host, etc. and to do things that were never possible before.

It is now possible to configure HA on RDS Custom with Always On Availability Groups, configuring the primary DB instance to synchronously replicate data to standby instances in different Availability Zones, but the process requires manual configuration. Reviewing the requirements and limitations of Amazon RDS Custom, Nitzan Israel, AWS cloud DBA at AllCloud, writes:

Two of the most important benefits we had in classic RDS (Read Replica HA solution and automatic minor version upgrades) were excluded from RDS Custom for SQL Server.

Amazon RDS Custom for SQL Server is based on licenses provided by AWS and currently supports Enterprise, Standard, and Web editions of SQL Server 2019. The service is now available in a subset of regions, including Northern Virginia and ‘Ireland. The price is higher than an equivalent classic RDS for SQL Server.


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