March 01, 2024

Smaller vSAN ESA ReadyNodes to Accommodate VMware vSphere Foundation’s Trial Capacity Capability

This post captures the very latest information in ReadyNodes certified for vSAN ESA configured in a vSAN HCI deployment.

The Express Storage Architecture (ESA) in VMware vSAN provides the ideal storage platform for environments powering their workloads through VMware Cloud Foundation or VMware vSphere Foundation.  Storage services are provided entirely by the hypervisor with extraordinary levels of performance, resilience, scalability and flexibility.  Using vSAN ESA, customers can choose if they want their clusters to be deployed using a traditional aggregated “vSAN HCI” deployment option, a blend of disaggregation using vSAN HCI with remote datastores, or a fully disaggregated deployment using vSAN Max.  No matter what is chosen, storage can be deployed and managed in a flexible, consistent, and cohesive manner, using the software you already know.

We are announcing changes to ReadyNodes certified for vSAN ESA used in aggregated vSAN HCI deployments that will lower the barrier of entry for many of our customers, and help align with licensing offerings as a part of the vSphere 8.0 P03 patch in VMware Cloud Foundation and VMware vSphere Foundation.  What does this improvement give you?  Potentially free vSAN storage capacity!

A complete matrix of ReadyNode profiles for vSAN HCI and vSAN Max can be found at: vSAN ESA ReadyNode Hardware Guidance but the latest changes are summarized below.

vSAN HCI - What's Changed

We’ve made several changes to vSAN ReadyNode profiles certified for use with vSAN ESA in an aggregated vSAN HCI deployment.

  • Reduced requirements for vSAN-ESA-AF-0 ReadyNodes.  These AF-0 ReadyNodes can now be configured with just a single NVMe device as small as 1.6TB.  This reduces the number of devices, and the amount of capacity required by half. While we still encourage the use of multiple storage devices for improved performance and resilience, this reduction can be ideal for several use cases.
  • Reduced requirements for vSAN-ESA-AF-2 ReadyNodes.  The minimum capacity of these AF-2 ReadyNodes have been reduced from 15TB per host down to 10TB per host.  The number of CPU cores per host have also been reduced from 32 cores per host down to 24 cores per host.
  • Reduced requirements for vSAN-ESA-AF-4 ReadyNodes.  The minimum number of CPU cores per host for this AF-4 ReadyNode profile have been reduced from 40 cores down to 32 cores. 

vSAN ReadyNodes Certified for vSAN HCI

Figure 1.  ReadyNode profiles certified for vSAN ESA in an aggregated vSAN HCI deployment.

How does the introduction of support of a single storage device for the vSAN-ESA-AF-0 ReadyNodes impact data resilience?  Unlike ReadyNodes with multiple storage devices, a failure of a storage device in a host would eliminate that host from participating in storage services, in effect acting like a host failure.  For this reason, it is highly recommended to have at least one or more hosts beyond the minimum required by the storage policy.  This will ensure that data can regain its prescribed level of resilience in the event of a discrete device failure for these ESA-AF-0 ReadyNodes.  When using ESA, having an extra host beyond what is required by the storage policy would translate to cluster sizes of 4 or more hosts for FTT=1 using RAID-5, and 7 or more hosts for FTT=2 using RAID-6.

Why it Matters

The reduction of resources with these specific ReadyNodes can shrink hardware costs for small data centers and edge environments.  The improvements also enable those who are using VMware vSphere Foundation to take advantage of the vSAN trial capacity provided as a part of the product.  VMware vSphere Foundation includes a vSAN trial capacity of 100 Gibibyte (GiB) per CPU core.  With the entry-level ReadyNode consisting of 16 cores per host, this effectively allows a 1.6TB device to take full advantage of the vSAN trial capacity included with VMware vSphere Foundation.  For example, a 4 host vSAN HCI cluster consisting of vSAN-ESA-AF-0 ReadyNodes would provide over 6TB of complimentary vSAN storage capacity, as a part of the VMware vSphere Foundation product licensing.

While the changes above apply to clusters running ESA, the new license model used with VMware Cloud Foundation and VMware vSphere Foundation apply to both ESA and the Original Storage Architecture (OSA).  The lower capacity minimums and broad compatibility with older, smaller storage devices for the OSA made it easier to take advantage of the VMware vSphere Foundation trial capacity.  The changes described above helps alleviate this matter for official ReadyNodes and ReadyNode emulated configurations certified for vSAN ESA.

Recommendation:  When possible, try to specify 4 or more storage devices in vSAN ESA hosts.  This provides performance and resilience benefits for vSAN clusters of any topology type.  It is particularly useful with 2-Node topologies, as it allows vSAN to storage the data using a secondary level of resilience in addition to the host-mirroring of a 2-host cluster.

Which to Choose?  vSAN HCI or vSAN Max?

For each cluster serving your VMware Cloud Foundation environment, vSAN can be provisioned in one of two deployment options: Aggregated clusters, known as "vSAN HCI" or disaggregated storage using vSAN Max providing storage for vSphere clusters.  A new document, "vSAN HCI or vSAN Max - Which Deployment Option is Right for You?" is available, and details some of the technical considerations that may help you determine which deployment option may be best for your environment.


For many years, aggregated vSAN HCI clusters have successfully powered workloads large and small, under a variety of conditions. The vSAN Express Storage Architecture, paired with new lower hardware minimums make vSAN HCI clusters more powerful than ever, and allowing you to take advantage of free trial capacity included in VMware vSphere Foundation.  Whether you choose an aggregated vSAN HCI deployment option, or a disaggregated vSAN Max deployment, the vSAN Express Storage Architecture is your best option for storage to power environments running VMware Cloud Foundation and VMware vSphere Foundation. 


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