Prerequisites for Azure HPC Cache

Before using the Azure portal to create a new Azure HPC Cache, make sure your environment meets these requirements.

Azure subscription

A paid subscription is recommended.


During the first several months of the GA release, the Azure HPC Cache team must add your subscription to the access list before it can be used to create a cache instance. This procedure helps ensure that each customer gets high-quality responsiveness from their caches. Fill out this form to request access.

Network infrastructure

Two network-related prerequisites should be set up before you can use your cache:

  • A dedicated subnet for the Azure HPC Cache instance
  • DNS support so that the cache can access storage and other resources

Cache subnet

The Azure HPC Cache needs a dedicated subnet with these qualities:

  • The subnet must have at least 64 IP addresses available.
  • The subnet cannot host any other VMs, even for related services like client machines.
  • If you use multiple Azure HPC Cache instances, each one needs its own subnet.

The best practice is to create a new subnet for each cache. You can create a new virtual network and subnet as part of creating the cache.

DNS access

The cache needs DNS to access resources outside of its virtual network. Depending on which resources you are using, you might need to set up a customized DNS server and configure forwarding between that server and Azure DNS servers:

  • To access Azure Blob storage endpoints and other internal resources, you need the Azure-based DNS server.
  • To access on-premises storage, you need to configure a custom DNS server that can resolve your storage hostnames.

If you only need access to Blob storage, you can use the default Azure-provided DNS server for your cache. However, if you need access to other resources, you should create a custom DNS server and configure it to forward any Azure-specific resolution requests to the Azure DNS server.

A simple DNS server also can be used to load balance client connections among all the available cache mount points.

Learn more about Azure virtual networks and DNS server configurations in Name resolution for resources in Azure virtual networks.


Check these permission-related prerequisites before starting to create your cache.

  • The cache instance needs to be able to create virtual network interfaces (NICs). The user who creates the cache must have sufficient privileges in the subscription to create NICs.

  • If using Blob storage, Azure HPC Cache needs authorization to access your storage account. Use role-based access control (RBAC) to give the cache access to your Blob storage. Two roles are required: Storage Account Contributor and Storage Blob Data Contributor.

    Follow the instructions in Add storage targets to add the roles.

Storage infrastructure

The cache supports Azure Blob containers or NFS hardware storage exports. Add storage targets after you create the cache.

Each storage type has specific prerequisites.

NFS storage requirements

If using on-premises hardware storage, the cache needs to have high-bandwidth network access to the datacenter from its subnet. ExpressRoute or similar access is recommended.

NFS back-end storage must be a compatible hardware/software platform. Contact the Azure HPC Cache team for details.

Blob storage requirements

If you want to use Azure Blob storage with your cache, you need a compatible storage account and either an empty Blob container or a container that is populated with Azure HPC Cache formatted data as described in Move data to Azure Blob storage.

Create the account before attempting to add a storage target. You can create a new container when you add the target.

To create a compatible storage account, use these settings:

  • Performance: Standard
  • Account kind: StorageV2 (general purpose v2)
  • Replication: Locally redundant storage (LRS)
  • Access tier (default): Hot

It's a good practice to use a storage account in the same location as your cache.

You also must give the cache application access to your Azure storage account as mentioned in Permissions, above. Follow the procedure in Add storage targets to give the cache the required access roles. If you are not the storage account owner, have the owner do this step.

Next steps