Total Pageviews

My YouTube Channel

Thursday, 10 December 2015

vSphere 5.5 Virtual SAN requirements (2058424)


This article provides information on the minimum requirements to create a Virtual SAN 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.


Virtual SAN requirements

Hardware requirements

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

Networking requirements

  • SSLv3 must be enabled at the vCenter level (vpxd) for storage policies to work correctly with VSAN
  • Each host must have a minimum of a single physical 1 GB Ethernet NIC available solely for Virtual SAN use
  • For more information on the Virtual SAN vSwitch configuration, see Configuring Virtual SAN VMkernel Networking (2058368)
  • For best performance, use Jumbo Frames.
  • Ensure Multicast is enabled. Multicast addresses can be changed if required.
For more information, see Virtual SAN 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
  • Virtual SAN requires sole access to the local disks of the host. Virtual SAN 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 Virtual SAN, 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:

Virtual SAN cluster nodes with no local storage

Not every host in the cluster needs storage. An ESXi host which is a Virtual SAN 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 Virtual SAN cluster named Testgroup running 32 virtual machines. The Virtual SAN 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 Virtual SAN 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 Virtual SAN datastore named TestDS.

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

Virtual machines stored on datastore TestDS are available to all Virtual SAN 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 Virtual SAN network to the local storage of the other nodes.

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

Licensing for Virtual SAN

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

License capacity and usage for Virtual SAN

Similar to vSphere licenses, Virtual SAN licenses have per CPU capacity. When you assign a Virtual SAN 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 Virtual SAN cluster that contains 4 hosts with 8 CPUs each, assign the cluster a Virtual SAN license with a minimum capacity of 32 CPUs.

The license usage of the Virtual SAN cluster is recalculated and updated when:
  • You assign a new license key to the Virtual SAN cluster
  • You add a new host to the Virtual SAN cluster
  • A host is removed from the cluster
  • The total number of CPUs in a cluster changes
Maintain the Virtual SAN clusters in compliance with the Virtual SAN licensing model. The total number of CPUs of all hosts in the cluster must not exceed the capacity of the Virtual SAN license that is assigned to the cluster.
All licensed editions of vSphere 5.5 are compatible with Virtual SAN. For more information, see the VMware Tribal Knowledge blog VMware Virtual SAN Now Available.

Virtual SAN for Desktop

Virtual SAN for Desktop is intended for use in VDI environments, such as vSphere for Desktop or VMware Horizon View. The license usage for Virtual SAN for Desktop equals the total number of powered on virtual machines in a cluster with enabled Virtual SAN.
To remain EULA compliant, the license usage for Virtual SAN for Desktop must not exceed the license capacity. The number of powered on desktop virtual machines in a Virtual SAN cluster must be less than or equal to the license capacity of Virtual SAN for Desktop.

License and evaluation period expiry

When the license or the evaluation period of a Virtual SAN expires, you can continue to use the currently configured Virtual SAN 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 Virtual SAN cluster

After you obtain an appropriate license key, assign it to your Virtual SAN cluster. Alternatively, use an existing Virtual SAN license key if one is available in the inventory of the vCenter Server system.
When you enable Virtual SAN for a cluster, use Virtual SAN in evaluation mode to explore its features. The evaluation period starts when Virtual SAN is enabled and expires after 60 days. To use Virtual SAN, 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 Virtual SAN.
  2. Click the Manage tab and then click Settings.
  3. Under Configuration, select Virtual SAN 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 Virtual SAN, click Decode.
      3. Click OK.
VMware KB 2058424