Bernardo
Bernardo

Reputation: 103

Why does Amazon RDS limits SQL Server databases to 30?

I understand is part of the Amazon RDS limits, but haven't found a comprehensive reason for it. Can anybody think of one? Maybe Microsoft licensing?

Here is AWS documentation on the issue:

You can create up to 30 databases on each of your DB instances running Microsoft SQL Server. The Microsoft system databases, such as master and model, don't count toward this limit.

Upvotes: 1

Views: 3022

Answers (1)

Hal Berenson
Hal Berenson

Reputation: 351

The RDS database limit exists to support Multi-AZ, which uses Microsoft SQL Server Mirroring. When Microsoft first introduced Mirroring they recommended a maximum of 10 mirrored databases per server (https://msdn.microsoft.com/en-us/library/ms366349(SQL.90).aspx). While the number of databases that can be mirrored has grown over time with increased numbers of faster processors and larger memories, there are still practical limits. Those limits are not just around performance and resource utilization, but extend to areas such as backup strategies. RDS took those into account in limiting the number of databases per instance to 30.

Upvotes: 3

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