Netherite Storage Provider is a backend implementation of Durable Functions that delivers high performance.

It's still a preview version, but if you are using Functions Premium (EP1-3), it's worth evaluating it now.

• Durable Functions storage providers - Azure | Microsoft Docs

The use of Netherite requires some additional work, so we will briefly introduce how to use it.

Install Netherite

First, install the Microsoft.Azure.DurableTask.Netherite.AzureFunctions package in your Azure Functions project.

• NuGet Gallery | Microsoft.Azure.DurableTask.Netherite.AzureFunctions

Install-Package Microsoft.Azure.DurableTask.Netherite.AzureFunctions -Version 0.4.0-alpha

dotnet add package Microsoft.Azure.DurableTask.Netherite.AzureFunctions --version 0.4.0-alpha

After installing the package, declare that you want to use Netherite in host.json. There are many configurations in the storageProvider, please refer to the official documentation.

{
  "version": "2.0",
  "logging": {
    "applicationInsights": {
      "samplingSettings": {
        "isEnabled": false,
        "excludedTypes": "Request"
      }
    },
  },
  "extensions": {
    "durableTask": {
      "hubName": "<YourHubName>",
      "useGracefulShutdown": true,
      "storageProvider": {
        "type": "Netherite",
        "StorageConnectionName": "AzureWebJobsStorage",
        "EventHubsConnectionName": "EventHubsConnection"
      }
    }
  }
}

Set the connection string names for Storage and Event Hubs to the key names in the Azure Functions App Settings or local.settings.json.

Preserve System.Threading.Channels.dll

The current version 0.4.0-alpha does not work with an error when deployed to Azure Functions, so you need to add FunctionsPreservedDependencies to the csproj file to avoid this problem.

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>netcoreapp3.1</TargetFramework>
    <AzureFunctionsVersion>v3</AzureFunctionsVersion>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="Microsoft.Azure.DurableTask.Netherite.AzureFunctions" Version="0.4.0-alpha" />
    <PackageReference Include="Microsoft.Azure.WebJobs.Extensions.DurableTask" Version="2.5.0" />
    <PackageReference Include="Microsoft.NET.Sdk.Functions" Version="3.0.13" />
  </ItemGroup>
  <ItemGroup>
    <FunctionsPreservedDependencies Include="System.Threading.Channels.dll" />
  </ItemGroup>
  <ItemGroup>
    <None Update="host.json">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
    </None>
    <None Update="local.settings.json">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
      <CopyToPublishDirectory>Never</CopyToPublishDirectory>
    </None>
  </ItemGroup>
</Project>

Add a setting to prevent System.Threading.Channels.dll from being removed on deployment. This fix will allow it to work on Azure Functions.

This problem is expected to be fixed in a future version.

Create Function App and Event Hubs

Create Function App and Event Hubs Namespace by using Azure Portal or ARM Template.

• Functions Premium (EP1-3)
  • Consumption Plan is not supported.
• Event Hubs Namespace (Standard, 1TU)
  • Event Hubs are automatically created by Netherite

Since Netherite creates the Event Hub automatically, it is easier to use RootManageSharedAccessKey for the SAS key.

Use 64-bit worker process

FASTER needs to run in a 64-bit process, so change the Platform setting of Azure Functions to 64-bit.

If you run the application with the 32-bit Platform setting, the following exception will be thrown at runtime and it will not work properly.

Part** !!! Encountered exception while working on store in StoreWorker.Process: FASTER.core.FasterException: Overflow in AddressInfo - consider running the program in x64 mode for larger address space support

Note that when you deploy Azure Functions (Windows) from Azure Portal, 32-bit Platform will be selected by default.

Enable Runtime Scale Monitoring

Durable Functions with Netherite installed running on Functions Premium (EP1-3) need to have Runtime Scale Monitoring enabled in order to scale out.

Since Runtime Scale Monitoring requires warmed-up instances, set preWarmedInstanceCount to 1 when creating resources with ARM Template or Terraform.

After these steps, Azure Functions using Netherite is now working perfectly. Now you can verify the performance and have fun.