Horizon 7 provides high-level guidelines that can help you determine how much storage an instant-clone or linked-clone desktop pool requires.

The storage-sizing table also displays the free space on the datastores that you select for storing OS disks, Composer persistent disks (for linked clones only), and replicas. You can decide which datastores to use by comparing the actual free space with the estimated requirements for the desktop pool.

The formulas that Horizon 7 uses can only provide a general estimate of storage use. The clones' actual storage growth depends on many factors:

  • Amount of memory assigned to the parent virtual machine
  • Frequency of refresh operations (for Composer linked clones only)
  • Size of the guest operating system's paging file
  • Whether you redirect paging and temp files to a separate disk (for Composer linked clones only)
  • Whether you configure separate Composer persistent disks (for Composer linked clones only)
  • Workload on the desktop machines, determined primarily by the types of applications that users run in the guest operating system
Note: In a deployment that includes hundreds or thousands of clones, configure your desktop pool so that particular sets of datastores are dedicated to particular ESXi clusters. Do not configure pools randomly across all the datastores so that most or all ESXi hosts must access most or all LUNs.

When too many ESXi hosts attempt to write to the OS disks on a particular LUN, contention problems can occur, degrading performance and interfering with scalability. For more information about datastore planning in large deployments, see the Horizon 7 Architecture Planning document.