In vSphere 5.1 and later, you can configure ESXi hosts to cache virtual machine disk data. This feature, called View Storage Accelerator, uses the Content Based Read Cache (CBRC) feature in ESXi hosts. View Storage Accelerator improves Horizon 7 performance during I/O storms, which can take place when many virtual machines start up or run anti-virus scans at once. The feature is also beneficial when administrators or users load applications or data frequently. Instead of reading the entire OS or application from the storage system over and over, a host can read common data blocks from cache.

About this task

By reducing the number of IOPS during boot storms, View Storage Accelerator lowers the demand on the storage array, which lets you use less storage I/O bandwidth to support your Horizon 7 deployment.

You enable caching on your ESXi hosts by selecting the View Storage Accelerator setting in the vCenter Server wizard in Horizon Administrator, as described in this procedure.

Make sure that View Storage Accelerator is also configured for individual desktop pools. To operate on a desktop pool, View Storage Accelerator must be enabled for vCenter Server and for the individual desktop pool.

View Storage Accelerator is enabled for desktop pools by default. The feature can be disabled or enabled when you create or edit a pool. The best approach is to enable this feature when you first create a desktop pool. If you enable the feature by editing an existing pool, you must ensure that a new replica and its digest disks are created before linked clones are provisioned. You can create a new replica by recomposing the pool to a new snapshot or rebalancing the pool to a new datastore. Digest files can only be configured for the virtual machines in a desktop pool when they are powered off.

You can enable View Storage Accelerator on desktop pools that contain linked clones and pools that contain full virtual machines.

Native NFS snapshot technology (VAAI) is not supported in pools that are enabled for View Storage Accelerator.

View Storage Accelerator is now qualified to work in configurations that use Horizon 7 replica tiering, in which replicas are stored on a separate datastore than linked clones. Although the performance benefits of using View Storage Accelerator with Horizon 7 replica tiering are not materially significant, certain capacity-related benefits might be realized by storing the replicas on a separate datastore. Hence, this combination is tested and supported.


If you plan to use this feature and you are using multiple View pods that share some ESXi hosts, you must enable the View Storage Accelerator feature for all pools that are on the shared ESXi hosts. Having inconsistent settings in multiple pods can cause instability of the virtual machines on the shared ESXi hosts.



  1. In Horizon Administrator, complete the Add vCenter Server wizard pages that precede the Storage Settings page.
    1. Select View Configuration > Servers.
    2. On the vCenter Servers tab, click Add.
    3. Complete the vCenter Server Information, View Composer Settings, and View Composer Domains pages.
  2. On the Storage Settings page, make sure that the Enable View Storage Accelerator check box is selected.

    This check box is selected by default.

  3. Specify a default host cache size.

    The default cache size applies to all ESXi hosts that are managed by this vCenter Server instance.

    The default value is 1,024MB. The cache size must be between 100MB and 2,048MB.

  4. To specify a different cache size for an individual ESXi host, select an ESXi host and click Edit cache size.
    1. In the Host cache dialog box, check Override default host cache size.
    2. Type a Host cache size value between 100MB and 2,048MB and click OK.
  5. On the Storage Settings page, click Next.
  6. Click Finish to add vCenter Server, View Composer, and Storage Settings to Horizon 7.

What to do next

To configure the PCoIP Secure Gateway, secure tunnel, and external URLs for client connections, see Configuring Horizon Client Connections.

To complete View Storage Accelerator settings in Horizon 7, configure View Storage Accelerator for desktop pools. See "Configure View Storage Accelerator for Desktop Pools" in the Setting Up Virtual Desktops in Horizon 7 document.