Storing session state data in an Azure environment

If you scale your projects to multiple instances, you must configure how session state information is stored. Session state must be stored either in the database, which is shared among the servers, or in a special service. Session state cannot be stored in the server’s memory – session information is lost whenever the request gets routed to another instance.

It is not necessary to configure shared session state between the live site and administration applications. However, you need to set up the session state storage for your MVC application if you want to scale it to use multiple Azure instances.

You have the following options for storing session state information in the Azure environment:

Storing session state information in Azure SQL Database

You need to perform the following steps to share session state across the scaled application:

  1. Open your project’s solution in Visual Studio.
  2. Right-click the web project and select Manage NuGet packages.
  3. Install the Microsoft.AspNet.Providers package.
  4. Open the web.config file.
  5. Follow the instructions in the code comments of the sessionState section.

After this, your project is configured to store session state information in the Microsoft Azure SQL Database.

Storing session state information in Azure Redis Cache

To configure your application to use Azure Redis Cache:

  1. Create a new Redis Cache according to the instructions in the Use Azure Redis Cache with a .NET application article.

  2. Open your project’s solution in Visual Studio.

  3. Right-click the solution and select Manage NuGet Packages.

  4. Search for and install the Microsoft.Web.RedisSessionStateProvider package.

    • This action automatically adds all required assembly references to the project and creates the following section in the web.config file:

        <sessionState mode="Custom" customProvider="MySessionStateStore">
              <add name="MySessionStateStore" 
                host = "" [String]
                port = "" [number]
                accessKey = "" [String]
                ssl = "false" [true|false]
                throwOnError = "true" [true|false]
                retryTimeoutInMilliseconds = "0" [number]
                databaseId = "0" [number]
                applicationName = "" [String]
                connectionTimeoutInMilliseconds = "5000" [number]
                operationTimeoutInMilliseconds = "5000" [number]
            <add name="MySessionStateStore" type="Microsoft.Web.Redis.RedisSessionStateProvider" host=""
            accessKey="..." ssl="true" />
    • Specify the host name and accessKey values which you can find in the properties of the cache service on Azure.

      Instead of inserting the values of the host and accessKey attributes directly, you can specify them as key-value pairs in the appSettings section of the application’s web.config file. You can then reference the values anywhere in the configuration file using their assigned keys.

        <add key="MyRedisAccessKey" value="...">

      Values stored in the appSettings section can be easily accessed and managed, for example, via the Azure Portal. The contents of the section can also be encrypted, preventing untrustworthy people from accessing application secrets, such as the Redis cache provider access key.

      See the official AspNet Redis documentation for details.

You can now deploy your project to Azure and start utilizing Azure Redis Cache as a session state provider.