Elastic pool in Azure SQL & SQL server Managed instance

Question

I have 2 doubts

1. ) What is the right explanation Elastic pool in Azure SQL ?
2. ) What is SQL server Managed instance that is often heard in Azure DB services & when one should use it.

I have been trying to understand its significance but did not get a clear explanation else where. Can anyone help me by answering in simple terms?

Thank you.

Answer 1

Azure SQL Database Elastic Pool is a shared resource model for Single Azure SQL PaaS databases to achieve higher resource utilization efficiency, and all the databases within an elastic pool share predefined resources within the same elastic pool. The emphasis of this offering is on a simplified database-scoped programming model for multi-tenant SaaS applications where the workload pattern is well defined and delivers high cost-effectiveness when serving many tenants.

SQL Database Managed Instance offers a simplified instance-scoped programming model that is like an on-premises SQL Server instance. The databases in Managed Instance share the resources allocated to the Managed Instance, and the Managed Instance also represents the management grouping for these databases. The emphasis of this offering is on high compatibility with the programming model of on-premises SQL Server and out-of-box support for the large majority of SQL Server features and accompanying tools/services.

Some high-level guidelines might be:

• Use Elastic pools if you need to group a large number of single database that don't need all instance Transact-SQL functionalities that exist in SQL Server.
• Use Managed Instance if you want to migrate a large number of SQL Server database that heavily use instance level features such as CLR, Service Broker, SQL Agent, etc.

Please read the comparison table on Azure documentation.

Answer 2

Dear Vinay,

No, Azure SQL Managed Instance doesn't provide Elastic Pool as it's provided by Azure SQL. Azure Managed Instance offers Instance Pool.

Instance pools make it possible to deploy multiple instances with shared resources, which provides a convenient and cost-effective infrastructure to migrate multiple databases from SQL Server instances without having to consolidate smaller and less compute-intensive workloads onto a larger SQL Managed Instance.

Instance pools in Azure SQL Managed Instance allow you to deploy multiple instances with shared resources onto a single underlying virtual machine within a virtual cluster.

The Elastic Pool offered by Azure SQL is at Database level where you assign the required H/W specs/ resources on Elastic Pool and then you provision DBs within this pool. The databases utilize the resources offered by the pool.

The Instace Pool provided by Azure MI is a group of instances as Azure MI is like an SQL Engine hosted in a VM. When you create an Azure MI you select the provisioned H/W resources and then you create DBs within this instance. While, as described above, when it comes to Azure SQL you provision the H/W resources on DB level.

The Instance Pool is in Preview Mode.

Hope this helps!

If you encounter any future issues, please feel free to contact us, and we will be pleased to assist you further.

If you have found the answer provided to be helpful, please click on the "Accept answer/Upvote" button so that it is useful for other members in the Microsoft Q&A community.

Regards,

Answer 3

Does the Elastic Pool model is only for Azure SQL or does it fit for Managed Instance as well ?