June 13, 2024

Starting Small with vSAN Max

We know vSAN Max can go big, but can it be for small environments?  Absolutely!  Read on to learn more.

Since its debut, vSAN Max has offered impressive levels of flexibility for our customers.  Built using the vSAN Express Storage Architecture (ESA), vSAN Max can not only provide extraordinary levels of storage capacity and performance, but it can also meet the modest, cost-conscious needs of smaller environments.  This post will look at how to start small with the highly flexible, integrated storage of vSAN Max you already own, courtesy of your VMware Cloud Foundation licenses.

Starting Small with Storage Capacity

The ability to start small with vSAN Max stems from a recent lowering of hardware and cluster requirements.  This has opened up new possibilities, allowing for vSAN Max clusters to be deployed with fewer hosts, using ReadyNodes that have lower hardware and network specifications.  Take a look at the post: "Greater Flexibility with vSAN Max through Lower Hardware and Cluster Requirements" for all of the recent changes. 

For example, a cluster consisting of just 4 hosts could be deployed quickly, providing fully integrated storage for your vSphere clusters, as shown in Figure 1.  It is a great way to augment your existing storage resources or try vSAN Max as your primary centralized shared storage solution for your environment.  Customers who are familiar with a vSAN HCI cluster will feel instantly comfortable with vSAN Max, since it provides the same look and feel of a vSAN HCI cluster.

Small vSAN Max cluster

Figure 1.  Introducing vSAN Max to an environment with a small cluster consisting of 4 hosts.

Perhaps what is most impressive about a very simple arrangement above is that a simple deployment like what is shown above allows you to easily take advantage of storage capabilities you already own.  Let's look at this in more detail.

Taking Advantage of Your Existing Licensing

vSAN is a part of your VMware Cloud Foundation licenses.  This means that any VCF licenses applied to your vSphere hosts entitles you to 1 TiB of vSAN storage per VCF core!  This licensed vSAN storage can be used in an aggregated vSAN HCI deployment, or a disaggregated deployment using vSAN Max.  Since you have a fully integrated storage solution available to use, why not use it? 

Let's use an example of a small deployment to see how this works, and how vSAN Max can be easily introduced into your environment.  Imagine the following scenario:

  • A compute environment consisting of 9 vSphere hosts. 

  • Each host has 32 physical cores, totaling 288 VCF cores. 

The licensing of the vSphere hosts would provide 288 TiB of complimentary vSAN storage.  To take advantage of this storage capacity without retrofitting or adjusting the existing vSphere hosts, a small vSAN Max cluster can be deployed.  In this example, we use the following:

  • A vSAN Max cluster that consists of 4 hosts using the entry-level vSAN-Max-SM ReadyNode profile and built with just under 100 TIB per host of storage capacity, providing about 396 TiB of total cluster capacity.

  • Each host would consist of 32 physical cores to ensure each host has sufficient resources for growth

The 396 TiB of capacity that the vSAN Max cluster provides would need to be licensed, but when the 288 VCF core licenses in the vSphere cluster are combined with the 128 VCF core licenses in the vSAN Max cluster, we have 416 TiB of storage entitlements.  This license entitlement is more than enough to meet the storage capabilities of this particular vSAN Max cluster.  

Licensing of small vSAN Max cluster

Figure 2.  A simple licensing example for a small environment using VMware Cloud Foundation.

In other words, this specific example demonstrates how customers could provision a centralized storage solution that provides around 400 TB of capacity for just the cost of 128 core licenses, and 4 small servers.   What if the vSAN Max cluster has more storage capacity than your entitlements?  Simply purchase the vSAN Add-on capacity license in 1 TiB increments to license the remaining capacity of the cluster.

Starting Small with Flexible Networking Options

Networking requirements for vSAN Max have sometimes been misinterpreted.  A vSAN Max cluster may have different networking requirements depending on the vSAN Max ReadyNode profile used.  In most cases, the networking requirement for vSAN Max ranges from 25Gb networking up to 100Gb Ethernet, but the requirement only applies to the connectivity between hosts within the vSAN Max cluster, not the vSphere hosts that mount the vSAN Max datastore.  As shown in Figure 3, the connectivity from the vSphere hosts that mount a vSAN Max datastore can use as little as 10Gb networking. 

vSAN Max networking

Figure 3.  Networking requirements for vSAN Max

As with any type of storage traffic, higher-speed network connectivity from the vSphere hosts to the vSAN Max cluster may be beneficial if there is network contention from the vSphere clusters to the vSAN Max cluster.  For more information on networking recommendations for a vSAN Max environment, see the document: "vSAN Max Design and Operational Guidance."

Recommendation:  Use at least 25Gb networking for the hosts that comprise your vSAN Max clusters.  25Gb networking has been available for nearly a decade, and helps drive better throughput, lower latency, and more consistent performance.  While vSAN Max does support 10Gb networking for intra-cluster vSAN traffic on the smallest ReadyNodes, vSAN Max will perform much better with networking connectivity of 25Gb or higher.

Taking Advantage of Incremental Scalability

Starting small and growing incrementally provides several benefits not found with traditional approaches to storage.  vSAN Max can be scaled in a much more effective way than traditional modular-based storage arrays.  For more information, see the post:  "vSAN Max and the Advantage of Scalability."

Figure 4 demonstrates how an organization can start with a small vSAN Max cluster and grow to meet the demands of the environment.  In this example, a 4 host vSAN Max cluster is deployed in an existing environment.  The existing vSphere clusters simply mount the datastore provided by vSAN Max.  As additional clusters are added, or perhaps the legacy storage array is decommissioned, the vSAN Max cluster can easily provide more capacity and aggregate performance by adding more hosts to the cluster.   This can be done slowly and incrementally, or all at once.  Just as with a vSAN HCI cluster, when new vSAN hosts are added to a vSAN Max cluster, the capacity of the datastore increases automatically.

vSAN Max scalability

Figure 4.  Incremental growth of storage resources with vSAN Max.

Once you have vSAN Max in place, you'll begin to enjoy the benefits of integrated storage.  You'll have end-to-end visibility and control of storage traffic, as well as easy policy-based management of your workloads.  And lets not forget, consistent management courtesy of vCenter Server and the vSphere Client UI.

Recommendation:  Use higher performance hardware to achieve faster storage performance.  With vSAN, performance of a VM is derived from the host hardware and the network used to interconnect the hosts in the vSAN cluster, not the cluster host count.  While increasing the host count of a cluster will increase the aggregate IOPS and bandwidth achieved by the cluster, in most cases it will not improve the discrete performance capabilities observed by the VM.  VM performance will be a function of the host hardware and network connectivity. 


vSAN Max provides fully integrated, centralized shared storage for environments large and small.  You can easily start small using VCF licensing you already own, and incrementally grow when and where it makes most sense.


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