Why vSAN is Best for VMware Cloud Foundation


VMware vSAN is enterprise-class, hyperconverged storage that is native to the industry-leading hypervisor, VMware vSphere. vSAN enables you to manage compute and storage in a single platform. It reduces the cost and complexity of traditional storage and takes the easiest path to hyperconverged infrastructure (HCI) and hybrid cloud. vSAN is also a core component in VMware Cloud Foundation. This document covers the value that HCI with vSAN, vSphere Virtual Volumes (vVols)-enabled SAN/NAS, and traditional SAN/NAS bring to Cloud Foundation. The best way to summarize it is “good, better, best” where traditional SAN/NAS is good, vVols is better, and vSAN delivers the best value with Cloud Foundation. The following chart summarizes why vSAN is best for Cloud Foundation.

VMware Cloud Foundation Value Chart


with vVols*


HCI server economics and scaling




Lifecycle mgmt. for compute, network, storage




Consistent operations on-premises, in cloud




Automated storage configuration




Automated storage network configuration




Integrated storage health checks




Built-in vRealize Operations dashboards




Storage telemetry with VMware Analytics Cloud




Policy-based management in vCenter Server




Per-VM resilience, capacity, QoS controls




vRealize Automation storage plugin




VM snapshot offload to storage array




Automated deployment in Cloud Foundation




*vVols support as principal storage has been added in Cloud Foundation 4.1.


VMware Cloud Foundation Value Chart



SDDC Manager

Cloud Foundation software component that provisions, manages, and monitors the logical and physical resources of a Cloud Foundation system.

Management Domain

vSphere cluster that runs infrastructure management components such as vCenter Server, NSX, SDDC Manager, and vRealize Log insight. It is automatically created on a four-node vSAN cluster. Only vSAN is supported for running workloads in a Management Domain.

Workload Domain

vSphere cluster combined with storage and networking into a single consumable entity. A workload domain can be created, expanded, and deleted as part of the SDDC lifecycle operations.

Principle Storage

Storage supported by vSphere that is used to store and run virtual machines and container volumes in Workload Domains.

Supplemental Storage

Storage supported by vSphere mainly for data at rest such as virtual machine templates, backup data, ISO images, etc. It is not used for running workloads.





vSAN for the Management Domain

Only vSAN is supported for running workloads in a Cloud Foundation Management Domain. vSAN provides reliable, fast storage to run nearly any workload including management and monitoring applications. Deployment and lifecycle tasks such as patches and upgrades are automated for the entire stack—compute, network, and storage—when vSAN is used with Cloud Foundation. The vSAN license for the Management Domain is included with Cloud Foundation licenses. This combination of availability, performance, and simplicity helps ensure an excellent user experience for administrators, operators, and application owners from Day-0 bring-up through Day-2 operations.

Workload Domain Storage

Principle Storage

Storage used for running virtual machines and containers in a Cloud Foundation Workload Domain must be on the VMware Compatibility Guide for Storage/SAN and it must be one of these storage types:

  • vSAN
  • NFS v3
  • VMFS on fiber channel

Note: VMware vSphere Virtual Volumes (vVols) is now supported for use as principle storage with Cloud Foundation 4.1.

vSphere 7 U1 Core Storage: vVols and VCF

Supplemental Storage

A wider variety of storage types and protocols such as iSCSI, NFS v3 and v4, and fiber channel are supported for use cases other than running workloads, e.g., virtual machine templates and backup data. Supplemental storage must be on the VMware Compatibility Guide for Storage/SAN and it must not interfere with SDDC Manager lifecycle management processes such as host maintenance mode and reboots.

If a storage type other than vSAN will be used as supplemental storage, VMware recommends storage that supports vVols. Similar to vSAN, vVols enables precise, per-VM management of service levels such as resilience and capacity consumption using storage policy-based management. This provides a consistent operational model for managing storage services. However, it is important to note that lifecycle management of vVols storage arrays is handled outside of Cloud Foundation.

Why vSAN is Best for Cloud Foundation

HCI Server Economics and Scaling

HCI powered by vSAN for Management and Workload domains can lower CapEx and OpEx costs. This is achieved through the deployment of standard x86 hardware with local drives—no need for dedicated storage arrays and storage networks. OpEx savings are realized through use of the same, familiar tools for management of on-premises and cloud-based resources. vSAN clusters are simple to expand by adding drives to existing hosts (scale up). SDDC Manager makes it easy to expand Workload domains one host or many at a time for incremental growth as required by business needs. Expansion is done without disruption to workloads.

Lifecycle Management for Compute, Network, and Storage

SDDC Manager automates the deployment and configuration of vSAN. It also handles patches and upgrades through tight integration with vSphere Update Manager. You can manage the full lifecycle of compute, networking, and storage when vSAN is used for storage in a Cloud Foundation environment. External array lifecycle management is handled separate from SDDC Manager.

Consistent Operations On-premises and in the Cloud

HCI in managed services such as VMware Cloud on AWS and VMware as a Service on Google Cloud along with VMware Cloud Partner Program members such as Microsoft Azure, IBM Cloud, and CenturyLink utilize vSAN. Storage policy-based management is used to manage storage on-premises and in the cloud. This consistent operating model reduces learning curves; helps avoid mistakes; provides predictable results; and ultimately minimizes operational costs.

Automated Storage Configuration

SDDC Manager automates the process of enabling and configuring vSAN including the creation of vSAN disk groups when a Management or Workload domain is provisioned. All other storage types require some manual setup such as zoning and masking LUNs to vSphere hosts as a prerequisite to using them with SDDC Manager.

Integrated Storage Health Checks

vSAN Health includes more than 50 health checks to verify the cluster is configured properly and operating at its highest potential. These checks are performed once per hour. They cover a variety of configuration items including hardware compatibility, cluster health, network, physical drives, and build recommendations. vSAN Health is automatically updated with new checks when the Customer Experience Improvement Program is enabled. This helps ensure the highest levels of availability and performance.

Built-in vRealize Operations Dashboards

The latest versions of vRealize Operations include built-in dashboards for HCI clusters powered by vSAN. There is no need for you to create custom dashboards to view performance, capacity, and health information. There is also a built-in troubleshooting dashboard to help speed up resolution times when there are issues.

The latest versions of vSAN and vRealize Operations also enable high-level dashboards directly in the vSphere Client. This feature provides access to the Overview, Cluster View, and Alerts dashboards without having to switch UIs. You can quickly and easily see the most important metrics in the vSphere Client. A link to the full vRealize Operations UI is also provided for provide quick access when deeper analysis is needed.

Storage Telemetry with VMware Analytics Cloud

vSAN includes a “phone home” capability called Support Insight that sends anonymous data to the VMware Analytics Cloud. This configuration and performance data can be used by VMware Global Support Services (GSS) to troubleshoot issues in a customer’s environment. The customer must first provide GSS with the UUID of their vCenter Server. There is no need to upload logs prior to starting the troubleshooting process. This can lead to faster problem resolution times.

This anonymous data is also used by VMware to better understand how VMware products are used. This information helps with decisions on product enhancements and direction, which benefits both VMware and its customers. New health checks are pushed down to customer environments through Support Insight as new issues and recommendations are discovered by VMware. These health checks lead to a better product experience by avoiding the issues and implementing the recommendations.

Policy-based Management in vCenter Server

vVols and vSAN are managed through per-VM storage policies. These policies consist of rules based on the type of storage in use. Storage Policy-based Management (SPBM) is a feature of vCenter Server.

Per-VM Resilience, Capacity, QoS Controls

SPBM enables precise management of storage services and service levels such as resilience, performance, capacity consumption, QoS, replication, snapshots, etc. Policies can be assigned at any time without disruption. There is no need to migrate VMs from one LUN/volume to another to provide different storage services to the workload. Per-VM storage policies enable you to assign storage services and specific service levels to each workload based on business needs.

VMware vRealize Automation Storage Plugin

vRealize Automation provides end-user, self-service, automated deployments of virtual machine and container infrastructures and applications. The latest version of the plugin enables the automation of storage policy assignments for vVols and vSAN. This blog article contains more information: SPBM plugin for vRealize Automation gets a refresh!

VM Snapshot Offload to Storage Array

VM snapshots in vSphere use a redo log approach for maintaining various point-in-time states of a virtual machine. The redo log method works fairly well but is subject to limitations and potential performance impact as a snapshot chain gets longer. vVols gets around these limitations by offloading snapshot functionality to the array. When a VM snapshot is requested, vSphere intercepts the request and redirects it to the vVols-enabled array to be handled natively. This improves the performance and stability of VM snapshots while maintaining the same management UI.

vSAN uses vSANsparse snapshots which are traditional redo-log snapshots. However, some aspects of the vSANsparse snapshots use host memory to provide improvements to performance and stability (versus redo-log snapshots on other storage types).

Automated Deployment in VMware Cloud Foundation

Cloud Foundation has the capability to use all three storage types in Management and Workload domains. However, there are some limitations to SAN/NAS:

  • Only vSAN can be used as storage in Management domains
  • vSAN and NFS storage can be used as primary storage in Workload domains
  • FC storage can only be used as secondary storage in Workload domains

The use of vSAN for both Management and Workload domains provides consistent deployment, operational, and lifecycle management models.


Cloud Foundation supports the use of multiple storage types. Storage arrays without vVols provides a good experience even with the need to perform some tasks manually. vVols-enabled arrays provide a better experience by enabling the use of per-VM storage policies to manage service levels. vSAN is the best option. vSAN is deployed by default for Management domains. Deployment of vSAN for Workload domains keeps a consistent operational model and enables full lifecycle management for compute, networking, and storage. HCI powered by vSAN is the ideal, standard building block for consistent infrastructure and operations on-premises and in the cloud.