September 13, 2023

Support for ReadyNode Emulated Configurations in vSAN ESA

Can customers build their own vSAN ReadyNode configuration?  Read on to find out the answer!

With the initial debut of the vSAN Express Storage Architecture (ESA) in vSAN 8 announced in August of 2022, VMware wanted to provide a simple way for customers to deploy clusters with appropriately sized hardware and network specifications.  The vSAN ReadyNode program for the ESA ensured that customers could purchase servers that were preconfigured to meet the specific hardware minimums for the ESA, while also providing sufficient flexibility to meet the capacity and performance requirements for the customer's environment.

VMware has not only made significant enhancements to the ESA in vSAN 8 U1 and vSAN 8 U2, but we've also improved hardware compatibility while providing an easy and flexible path for customers and partners to build a supported configuration.  Let's look at what is supported.

Flexibility of the ReadyNode Program

Thanks to the expanded hardware compatibility with Read-Intensive storage devices, and the introduction of the new vSAN-ESA-AF-0 ReadyNodes for small data centers and edge environments, the type of hardware compatible with the ESA is more flexible than ever.  vSAN ReadyNodes can not only be procured using a simple, single SKU, but vSAN ESA-compliant configurations can also be achieved using an approach where a ReadyNode configuration is emulated using individual hardware components from approved ReadyNode vendors.

This means that customers can pick a server manufacturer’s ESA certified ReadyNode platform listed on the VMware Compatibility Guide (VCG) for vSAN ESA, and can build out a server configuration using hardware components as they are listed on the given ReadyNode specification, emulating a ReadyNode purchased using a single SKU.  This approach can help customers who chose not to purchase a ReadyNode through an official SKU but have the same or better hardware found in the desired ReadyNode classification.

The term “ReadyNode emulated” simply refers to how the ReadyNode was procured.  It is seen and supported by VMware and the ReadyNode vendors in the very same way as ReadyNodes purchased using a single SKU.

Supported paths to build an ESA cluster

Figure 1.  Supported paths to build your vSAN ESA cluster.

The support of these ReadyNode emulated systems provides tremendous flexibility in hardware procurement and deployment of servers that can run vSAN ESA.  This option applies to hardware and platforms certified for ESA, not for off-the-shelf, generic server hardware by non-ReadyNode vendors.  That type of “build your own” or BYO approach is available only when using the vSAN Original Storage Architecture, or OSA.  The VCG for vSAN ESA still uses a select list of approved ReadyNode vendors using hardware certified for vSAN ESA.

Tips for Successful Configurations

The ability to configure supported systems using single SKU vSAN ReadyNodes or emulated ReadyNodes is a powerful combination for our customers.  While this does offer tremendous flexibility, the following recommendations will help ensure the proper compatibility and support.

  • Check (and recheck) to ensure the hardware selected is the same as what is listed on the desired ReadyNode in the VMware Compatibility Guide (VCG) for vSAN ESA.  The VCG for vSAN is the tool to determine the compatibility of a discrete component for ReadyNode servers using the ESA.  This will provide the proper guidance to check that the hardware components you select are certified for vSAN ESA.  The server configuration must be equal to, or better than the minimums defined in the vSAN ESA ReadyNode classifications
  • Use the vSAN ReadyNode Sizer to determine your minimum host specifications.  The vSAN ReadyNode Sizer is a great tool to determine the size of a cluster and the hardware specifications of a host to meet your capacity and performance needs.  The output will apply to official ReadyNode SKUs, and the ReadyNode emulated systems.
  • Follow the vSAN ESA ReadyNode Hardware Guidance for properly balanced configurations of CPU, memory, network, and storage.  The vSAN ESA ReadyNode Hardware Guidance link defines the hardware minimum requirements for each respective ReadyNode profile or classification.  The ReadyNode classes for the ESA help provide a balanced configuration and ensure a base level of performance, consistency, and efficiency for customers.  See VMware KB 90343 to understand what you can and cannot change in a vSAN ReadyNode.
  • Pay attention to hardware specifications for high-performance requirements.  The vSAN ReadyNode sizer will help ensure the proper vSAN ReadyNode profile is chosen that reflects the desired performance and capacity requirements.  This will help prevent you from building servers that resemble perhaps a vSAN-ESA-AF-2 for resource-intensive workloads that are a better fit for a higher-performing ReadyNode profile.  Also, look at the "Performance Recommendations for vSAN ESA" for more general guidance about optimal performance settings for vSAN ESA.
  • Ensure that ESA hosts do NOT use tri-mode controllers.  Some server vendors may inadvertently use a controller that supports multiple bus interfaces, known as a tri-mode controller.  The use of tri-mode controllers when using NVMe storage devices is not supported in vSAN ESA.  NVMe devices have their own embedded controller, and for vSAN ESA, they should be directly attached to a PCIe slot in the server.  See VMware KB 88722 for more information.
  • Be sure to include Trusted Platform Modules (TPMs) in each vSAN ESA host.  TPMs are an affordable and easy way to ensure that security keys issued to hosts can be stored securely and reliably.  Even if you don't plan on using vSAN encryption services in the short term, be sure to include TPMs in the build specification so that key distribution is as robust as possible when encryption services are enabled.
  • Become familiar with your vendor’s Hardware Support Module (HSM) used with vSphere Lifecycle Manager (vLCM).  The vendor provided HSM is one of the critical components of vLCM and helps ensure that your ReadyNode servers are running the appropriate firmware and drivers for the hypervisor, and will aid in the lifecycle management of the servers once the servers are in production.


The vSAN ReadyNode program for ESA, and its associated compatibility guide helps customers build server configurations that have been tested to deliver the highest levels of performance, stability, and predictability.  The expanded compatibility of hardware paired with the purchasing flexibility of vSAN ReadyNodes makes purchasing servers for vSAN ESA easy, flexible, and affordable.



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