SQL Server Database options in Azure

Microsoft Azure primarily offers following options for SQL Server requirements:

Azure SQL Database (or SQL Database): A fully-managed SQL database engine, based on the latest stable SQL Server. This falls into the category of Platform-as-a-Service (PaaS).

Azure SQL Database comes in 3 flavours:

1. Single database: As a single database with its own set of resources managed via a SQL Database server

2. Elastic pool: a collection of databases with a shared set of resources managed via a SQL Database server. Single databases can be moved into and out of an elastic pool.

3. Managed instance: provides all of the PaaS benefits of Azure SQL Database but adds capabilities that were previously only available in SQL VMs.

SQL Server on Azure Virtual Machines: allows users to run SQL Server inside a fully-managed Windows Server or Linux VM in the Azure cloud. It falls into the category of Infrastructure-as-a-Service (IaaS).

This page describes and compares the different options in great detail.

Below is a summary of the same:

The table here gives more in depth comparison between the three options from cost/business perspective. Once again to summarise: while SQL Server on VM gives full control and flexibility, with great power comes great responsibility, which means entire effort of managing the health of DB and VM will have to be done by us and considering the number of customers this will not be an easy task.

Single Database/Elastic Pool rule themselves out because of the number of missing features. Here is a SQL feature comparison between Single DB and Managed Instances.

As you might have read that Managed Instances support ‘almost all’ SQL Server features with exception of ‘few’ unsupported ones. Here is a real detailed comparison between SQL Server and Managed instance. This comparison needs to be checked carefully to see if there are any missing features which are really critical or the workarounds mentioned are good enough.