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vSphere 5.5 vSAN requirements (2058424)

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This article provides information on the minimum requirements to create a vSAN cluster in vSphere 5.5.

For more information, see the vSphere 5.5 documentation. The documentation contains definitive information. If there is a discrepancy between the documentation and this article, assume that the documentation is correct.


vSAN requirements

vSphere version requirements

To deploy vSAN (formerly known as vSAN), you must be running vSphere 5.5 Update 1 or later. Any previous builds of ESXi or vCenter Server are not supported for vSAN.

Hardware requirements

All hardware used for a vSAN deployment must be on the VMware HCL. All I/O Controllers, HDD and SSD must be on the vSAN HCL.

Warning: Using uncertified hardware may lead to performance issues and/or data loss. The reason for this is that the behavior of uncertified hardware cannot be predicted. VMware cannot provide support for environments running on uncertified hardware.

Host requirements

  • A minimum of three ESXi 5.5 hosts, all contributing local disks (1 SSD and 1 HDD)
  • Each host must have a minimum of 6 GB of RAM
  • The host is managed by vCenter Server 5.5 and configured as a vSAN cluster

Networking requirements

  • For releases prior to VMware vSphere 5.5 Update 3, SSLv3 must be enabled in order for storage policies to work with vSAN. If you have a requirement where SSLv3 must be disabled in your environment, ensure that you are running vSphere 5.5 Update 3 or later as SSLv3 is no longer required from that release onward.
  • Each host must have a minimum of a single physical 1 GB Ethernet NIC available solely for vSAN use
  • For more information on the vSAN vSwitch configuration, see Configuring vSAN VMkernel Networking (2058368)
  • For best performance, use Jumbo Frames.
  • Ensure Multicast is enabled. Multicast addresses can be changed if required.
For more information, see vSAN Networking Requirements and Best Practices in the vSphere 5.5 Storage Guide.

Storage requirements

  • At least 1 SAS or SATA Solid State Drive (SSD)

    • Ensure that vSphere Flash Read Cache does not claim SSD
    • Do not format SSDs with VMFS or any other file system
  • At least 1 SAS or SATA Hard Disk (HDD)
  • A SAS or SATA Host Bus Adapter (HBA), or RAID controller that is set up in non-RAID (pass through) mode
  • vSAN requires sole access to the local disks of the host. vSAN disks are not shared with another file system, such as Virtual Flash File System (VFFS), VMFS partitions, or an ESXi boot partition.
  • If you install ESXi on a USB or SD device and allocate all local storage to vSAN, you do not have any local disk or datastore available for persistent logging. Configure a Dump Collector and a Syslog Collector to direct ESXi memory dumps and system logs to a server on the network, rather than to a local disk.

    For more information, see:

vSAN cluster nodes with no local storage

Not every host in the cluster needs storage. An ESXi host which is a vSAN cluster node starts from SAN, SD/USB, or local disk. Virtual machines then run in memory, reading virtual machine files from the local disks of other cluster nodes.

For example, consider this sample environment:

A 4-node vSAN cluster named Testgroup running 32 virtual machines. The vSAN cluster nodes in Testgroup are:
  • ESX1 – Has 1 SSD and 1 HDD
  • ESX2 – Has 1 SSD and 1 HDD
  • ESX3 – Has 1 SSD and 1 HDD
  • ESX4 – Has no local storage and is starting from SAN
  • A vSAN datastore is created from the available local storage
The 3 SSDs and 3 HDDs in hosts ESX1, ESX2, and ESX3 are used to create a 500 GB vSAN datastore named TestDS.

Note: SSDs do not contribute to the capacity of the vSAN Datastore. SSDs are used only for read cache and write buffering.

Virtual machines stored on datastore TestDS are available to all vSAN cluster member hosts.

Host ESX4 is running virtual machines stored on the TestDS datastore. The pieces of those virtual machines are physically located on storage which is locally attached to another cluster node. The virtual machine runs in the memory of host ESX4, but the read and write data is sent across the vSAN network to the local storage of the other nodes.

For more information on vSAN requirements, see Requirements for vSAN in the vSphere 5.5 Storage Guide.

Licensing for vSAN

When you enable vSAN on a cluster, assign the cluster an appropriate vSAN license before the 60-day evaluation period expires.

License capacity and usage for vSAN

Similar to vSphere licenses, vSAN licenses have per CPU capacity. When you assign a vSAN license to a cluster, the amount of license capacity that is used equals the total number of CPUs in the hosts that participate in the cluster. For example, if you have a vSAN cluster that contains 4 hosts with 8 CPUs each, assign the cluster a vSAN license with a minimum capacity of 32 CPUs.

The license usage of the vSAN cluster is recalculated and updated when:

  • You assign a new license key to the vSAN cluster
  • You add a new host to the vSAN cluster
  • A host is removed from the cluster
  • The total number of CPUs in a cluster changes

Maintain the vSAN clusters in compliance with the vSAN licensing model. The total number of CPUs of all hosts in the cluster must not exceed the capacity of the vSAN license that is assigned to the cluster.

All licensed editions of vSphere 5.5 are compatible with vSAN. For more information, see the VMware Tribal Knowledge blog VMware vSAN Now Available.

vSAN for Desktop

vSAN for Desktop is intended for use in VDI environments, such as vSphere for Desktop or VMware Horizon View. The license usage for vSAN for Desktop equals the total number of powered on virtual machines in a cluster with enabled vSAN.

To remain EULA compliant, the license usage for vSAN for Desktop must not exceed the license capacity. The number of powered on desktop virtual machines in a vSAN cluster must be less than or equal to the license capacity of  vSAN for Desktop.

License and evaluation period expiry

When the license or the evaluation period of a vSAN expires, you can continue to use the currently configured vSAN resources and features. However, you cannot add more hosts to the cluster or increase the SSD capacity on each host.

Assigning a license key to a vSAN cluster

After you obtain an appropriate license key, assign it to your vSAN cluster. Alternatively, use an existing vSAN license key if one is available in the inventory of the vCenter Server system.

When you enable vSAN for a cluster, use vSAN in evaluation mode to explore its features. The evaluation period starts when vSAN is enabled and expires after 60 days. To use vSAN, you must license the cluster before the evaluation period expires.


  • Required privilege: Global.Licenses
  • If you plan to assign an existing license, verify that the license key is available in the vCenter Server system


  1. In the vSphere Web client, navigate to a cluster with enabled vSAN.
  2. Click the Manage tab and then click Settings.
  3. Under Configuration, select vSAN licensing and click Assign License Key.
  4. Select one of these licensing options:
    • Assign an existing license key and then click OK.
    • Assign a new license key using these steps:
      1. Type or copy and paste the license key and type an optional label for the key.
      2. To verify that the license key is in the correct format, and that it is for vSAN, click Decode.
      3. Click OK.

See Also

Request a Product Feature

To request a new product feature or to provide feedback on a VMware product, please visit the Request a Product Feature page.


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