When you create a linked-clone desktop pool, you can configure certain options. Use this worksheet to prepare your configuration options before you create the linked-clone desktop pool.

Before you create a linked-clone pool, you must use vCenter Server to take a snapshot of the parent virtual machine that you prepare for the pool. You must shut down the parent virtual machine before you take the snapshot. Horizon Composer uses the snapshot as the base image from which the clones are created.
Note: You cannot create a linked-clone pool from a virtual machine template.
Table 1. Worksheet: Configuration Options for Creating a Linked-Clone Desktop Pool
Option Description Fill In Your Value Here
vCenter Server Select the vCenter Server that manages the virtual machines in the pool.
User assignment Choose the type of user assignment:
  • In a dedicated-assignment pool, each user is assigned to a machine. Users receive the same machine each time they log in.
  • In a floating-assignment pool, users receive different machines each time they log in.
Enable automatic assignment In a dedicated-assignment pool, a machine is assigned to a user when the user first logs in to the pool. You can also explicitly assign machines to users.

If you do not enable automatic assignment, you must explicitly assign a machine to each user.

Persistent disk If you select dedicated user assignments, choose whether to store Windows user-profile data on a separate Horizon Composer persistent disk or the same disk as the OS data.
  • Redirect Windows profile to a persistent disk. Select this option to store data on a separate Horizon Composer persistent disk. Separate persistent disks let you preserve user data and settings. Horizon Composer refresh, recompose, and rebalance operations do not affect persistent disks. You can detach a persistent disk from a linked clone and recreate the linked-clone virtual machine from the detached disk. For example, when a machine or pool is deleted, you can detach the persistent disk and recreate the desktop, preserving the original user data and settings.
  • Disk size. If you store user profile data on a separate Horizon Composer persistent disk, provide the disk size in megabytes.
  • Drive letter. If you store user profile data on a separate Horizon Composer persistent disk, provide the drive letter.
    Note: Do not select a drive letter that already exists on the parent virtual machine or that conflicts with a drive letter that is used for a network-mounted drive.
  • Do not redirect Windows profile. Select this option if you store the Windows profile in the OS disk. The user data and settings are removed during refresh, recompose, and rebalance operations.
Disposable File Redirection Choose whether to redirect the guest operating system's paging and temporary files to a separate, non-persistent disk.
  • Redirect disposable files to a non-persistent disk. Select this option to redirect the guest operating system's paging and temporary files to a separate, non-persistent disk. With this configuration, when a linked clone is powered off, the disposable-file disk is replaced with a copy of the original disk that was created with the linked-clone pool. Linked clones can increase in size as users interact with their desktops. Disposable file redirection can save storage space by slowing the growth of linked clones.
  • Disk size. If you redirect disposable files to a non-persistent disk, provide the disk size in megabytes.

    The disk size should be larger than page-file size of the guest OS. To determine the page-file size, see "Keep a Record of the Parent Virtual Machine's Paging-File Size" in the Setting Up Virtual Desktops in Horizon 7 document. When you configure the disposable file disk size, consider that the actual size of a formatted disk partition is slightly smaller than the value you provide in Horizon Console.

  • Drive letter. If you redirect disposable files to a non-persistent disk, provide the drive letter. You can select a drive letter for the disposable file disk. The default value, Auto, directs Horizon 7 to assign the drive letter.
  • Do not redirect disposable files. Select this option if you do not want to redirect the guest operating systems paging and temporary files.
    Note: Do not select a drive letter that already exists on the parent virtual machine or that conflicts with a drive letter that is used for a network-mounted drive.
Use VMware vSAN Specify whether to use VMware vSAN, if available. vSAN is a software-defined storage tier that virtualizes the local physical storage disks available on a cluster of ESXi hosts. For more information, see "Using vSAN for High-Performance Storage and Policy-Based Management" in the Setting Up Virtual Desktops in Horizon 7 document.
Select separate datastores for persistent and OS disks (Available only if you do not use vSAN) If you redirect user profiles to separate persistent disks, you can store the persistent disks and OS disks on different datastores.
Select separate datastores for replica and OS disks (Available only if you do not use vSAN or Virtual Volumes) You can store the replica (master) virtual machine disk on a high performance datastore and the linked clones on separate datastores.

For details, see the Setting Up Virtual Desktops in Horizon 7 document.

If you store replicas and OS disks on separate datastores, native NFS snapshots cannot be used. Native cloning on a NAS device can only take place if the replica and OS disks are stored on the same datastores.

Desktop Pool ID The unique name that identifies the pool.

If multiple Connection Server configurations are running in your environment, make sure that another Connection Server configuration is not using the same pool ID.

A Connection Server configuration can be a standalone Connection Server instance or a pod of replicated instances that share a common View LDAP configuration.

Display name The pool name that users see when they log in from a client device. If you do not specify a display name, the pool ID is displayed to users.
Access group Select an access group in which to place the pool or leave the pool in the default root access group.

If you use an access group, you can delegate managing the pool to an administrator who has a specific role. For details, see the role-based delegated administration chapter in the Horizon 7 Administration document.

Note: Access groups are different from vCenter Server folders that store virtual machines that are used as desktops. You select a vCenter Server folder later in the wizard with other vCenter Server settings.
Enable provisioning Select this option to provision virtual machines in a desktop pool.
Stop provisioning on error You can direct Horizon 7 to stop provisioning or continue to provision virtual machines in a desktop pool after an error occurs during the provisioning of a virtual machine. If you leave this setting selected, you can prevent a provisioning error from recurring on multiple virtual machines.
Virtual machine naming Choose whether to provision machines by manually specifying a list of machine names or by providing a naming pattern and the total number of machines.

For details, see Naming Machines Manually or Providing a Naming Pattern in Horizon Console.

Specify names manually If you specify names manually, prepare a list of machine names and, optionally, the associated user names.
Naming pattern If you use this naming method, provide the pattern.

The pattern you specify is used as a prefix in all the machine names, followed by a unique number to identify each machine.

For details, see Using a Naming Pattern for Automated Desktop Pools.

Max number of machines If you use a naming pattern, specify the total number of machines in the pool.

You can also specify a minimum number of machines to provision when you first create the pool.

Number of spare (powered on) machines If you specify names manually or use a naming pattern, specify a number of machines to keep available and powered on for new users. For details, see Naming Machines Manually or Providing a Naming Pattern in Horizon Console.

When you specify names manually, this option is called # Unassigned machines kept powered on.

Minimum number of ready (provisioned) machines during Horizon Composer maintenance operations If you specify names manually or use a naming pattern, specify a minimum number of machines that are provisioned for use in remote desktop sessions while Horizon Composer maintenance operations take place.

This setting allows users to maintain existing connections or make new connection requests while Horizon Composer refreshes, recomposes, or rebalances the machines in the pool. The setting does not distinguish between spare machines that are ready to accept new connections and machines that are already connected in existing desktop sessions.

This value must be smaller than the Max number of machines, which you specify if you provision machines on demand.

For more information, see the Setting Up Virtual Desktops in Horizon 7 document.

Provision machines on demand

or

Provision all machines up front

If you use a naming pattern, choose whether to provision all machines when the pool is created or provision machines as they are needed.
  • Provision all machines up front. When the pool is created, the system provisions the number of machines you specify in Max number of machines.
  • Provision machines on demand. When the pool is created, the system creates the number of machines that you specify in Min number of machines. Additional machines are created as users connect to the pool for the first time or as you assign machines to users.
Min number of machines If you use a naming pattern and provision desktops on demand, specify a minimum number of machines in the pool.

The system creates the minimum number of machines when you create the pool. This number is maintained even when other settings such as Delete or refresh machine on logoff cause machines to be deleted.

Parent VM Select the parent virtual machine for the pool.
Snapshot (default image) Select the snapshot of the parent virtual machine to use as the base image for the pool.

Do not delete the snapshot and parent virtual machine from vCenter Server, unless no linked clones in the pool use the default image, and no more linked clones will be created from this default image. The system requires the parent virtual machine and snapshot to provision new linked clones in the pool, according to pool policies. The parent virtual machine and snapshot are also required for Horizon Composer maintenance operations.

VM folder location Select the folder in vCenter Server in which the desktop pool resides.
Host or cluster Select the ESXi host or cluster on which the desktop virtual machines run.

With vSAN datastores (a vSphere 5.5 Update 1 feature), you can select a cluster with up to 20 ESXi hosts. With Virtual Volumes datastores (a vSphere 6.0 feature), you can select a cluster with up to 32 ESXi hosts.

In vSphere 5.1 or later, you can select a cluster with up to 32 ESXi hosts if the replicas are stored on VMFS5 or later datastores or NFS datastores. If you store replicas on a VMFS version earlier than VMFS5, a cluster can have at most eight hosts.

In vSphere 5.0, you can select a cluster with more than eight ESXi hosts if the replicas are stored on NFS datastores. If you store replicas on VMFS datastores, a cluster can have at most eight hosts. See, "Configuring Desktop Pools on Clusters With More Than Eight Hosts," in the Setting Up Virtual Desktops in Horizon 7 document.

Resource pool Select the vCenter Server resource pool in which the desktop pool resides.
Linked clone datastores Select one or more datastores on which to store the desktop pool.

A table on the Select Linked Clone Datastores page of the Add Pool wizard provides high-level guidelines for estimating the pool's storage requirements. These guidelines can help you determine which datastores are large enough to store the linked-clone disks. For details, see "Storage Sizing for Linked-Clone Desktop Pools," in the Setting Up Virtual Desktops in Horizon 7 document.

You can use shared or local datastores for an individual ESXi host or for ESXi clusters. If you use local datastores in an ESXi cluster, you must consider the vSphere infrastructure constraints that are imposed on your desktop deployment. See, "Storing Linked Clones on Local Datastores," in the Setting Up Virtual Desktops in Horizon 7 document.

With vSAN datastores (a vSphere 5.5 Update 1 feature), you can select a cluster with up to 20 ESXi hosts. With Virtual Volumes datastores (a vSphere 6.0 feature), you can select a cluster with up to 32 ESXi hosts.

For more information about the disks that are created for linked clones, see "Linked-Clone Data Disks," in the Setting Up Virtual Desktops in Horizon 7 document.

Note: If you use vSAN, select only one datastore.
Replica disk datastores Select a replica disk datastore on which to store the replicas.

In vSphere 5.1 or later, a cluster can have more than eight ESXi hosts if the replicas are stored on datastores that are VMFS5 or later or NFS. In vSphere 5.0, a cluster can have more than eight ESXi hosts only if the replicas are stored on NFS datastores. See, "Configuring Desktop Pools on Clusters With More Than Eight Hosts," in the Setting Up Virtual Desktops in Horizon 7 document.

Delete or refresh machine on logoff If you select floating user assignment, choose whether to refresh machines, delete machines, or do nothing after users log off.
Note: You set this option on the Desktop Pool Settings page.
Desktop Pool Settings Settings that determine the machine state, power status when a virtual machine is not in use, display protocol, Adobe Flash quality, and so on.

For descriptions, see "Desktop Pool Settings for All Desktop Pool Types," in the Setting Up Virtual Desktops in Horizon 7 document.

For a list of the settings that apply to linked-clone pools, see Desktop Pool Settings for Linked-Clone Desktop Pools in Horizon Console.

For more information about power policies and automated pools, see "Setting Power Policies for desktop Pools in the Setting Up Virtual Desktops in Horizon 7 document.

Use Horizon Storage Accelerator Determine whether to use Horizon Storage Accelerator, which allows ESXi hosts to cache common virtual machine disk data. Horizon Storage Accelerator can improve performance and reduce the need for extra storage I/O bandwidth to manage boot storms and anti-virus scanning I/O storms.

This feature is supported on vSphere 5.0 and later.

This feature is enabled by default.

For details, see the Setting Up Virtual Desktops in Horizon 7 document.

Storage Overcommit Determine the storage-overcommit level at which linked-clones are created on each datastore.

As the level increases, more linked clones fit on the datastore and less space is reserved to let individual clones grow. A high storage-overcommit level lets you create linked clones that have a total logical size larger than the physical storage limit of the datastore. For details, see "Set the Storage Overcommit Level for Linked-Clone Virtual Machines," in the Setting Up Virtual Desktops in Horizon 7 document.

Note: This setting has no effect if you use vSAN.
Use native NFS snapshots (VAAI) (Available only if you do not use vSAN) If your deployment includes NAS devices that support the vStorage APIs for Array Integration (VAAI), you can use native snapshot technology to clone virtual machines.

You can use this feature only if you select datastores that reside on NAS devices that support native cloning operations through VAAI.

You cannot use this feature if you store replicas and OS disks on separate datastores. You cannot use this feature on virtual machines with space-efficient disks.

This feature is supported on vSphere 5.0 and later.

For details, see the Setting Up Virtual Desktops in Horizon 7 document.

Reclaim VM disk space (Available only if you do not use vSAN or Virtual Volumes) Determine whether to allow ESXi hosts to reclaim unused disk space on linked clones that are created in space-efficient disk format. The space reclamation feature reduces the total storage space required for linked-clone desktops.

This feature is supported on vSphere 5.1 and later. The linked-clone virtual machines must be virtual hardware version 9 or later.

For details, see "Reclaim Disk Space on Linked-Clone Virtual Machines," in the Setting Up Virtual Desktops in Horizon 7 document.

Initiate reclamation when unused space on VM exceeds: (Available only if you do not use vSAN or Virtual Volumes) Type the minimum amount of unused disk space, in gigabytes, that must accumulate on a linked-clone OS disk to trigger space reclamation. When the unused disk space exceeds this threshold, Horizon 7 initiates the operation that directs the ESXi host to reclaim space on the OS disk.

This value is measured per virtual machine. The unused disk space must exceed the specified threshold on an individual virtual machine before Horizon 7 starts the space reclamation process on that machine.

For example: 2 GB.

The default value is 1 GB.

Blackout Times Configure days and times during which Horizon Storage Accelerator regeneration and the reclamation of virtual machine disk space do not take place.

To ensure that ESXi resources are dedicated to foreground tasks when necessary, you can prevent the ESXi hosts from performing these operations during specified periods of time on specified days.

For details, see "Set Blackout Times for ESXi Operations on Virtual Machines," in the Setting Up Virtual Desktops in Horizon 7 document.

Transparent Page Sharing Scope

Select the level at which to allow transparent page sharing (TPS). The choices are Virtual Machine (the default), Pool, Pod, or Global. If you turn on TPS for all the machines in the pool, pod, or globally, the ESXi host eliminates redundant copies of memory pages that result if the machines use the same guest operating system or applications.

Page sharing happens on the ESXi host. For example, if you enable TPS at the pool level but the pool is spread across multiple ESXi hosts, only virtual machines on the same host and within the same pool will share pages. At the global level, all machines managed by Horizon 7 on the same ESXi host can share memory pages, regardless of which pool the machines reside in.

Note: The default setting is not to share memory pages among machines because TPS can pose a security risk. Research indicates that TPS could possibly be abused to gain unauthorized access to data in very limited configuration scenarios.
Domain Select the Active Directory domain and user name.

Horizon Composer requires certain user privileges to create a linked-clone pool. The domain and user account are used by QuickPrep or Sysprep to customize the linked-clone machines.

You specify this user when you configure Horizon Composer settings for vCenter Server. You can specify multiple domains and users when you configure Horizon Composer settings. When you use the Add Desktop Pool wizard to create a pool, you must select one domain and user from the list.

AD container Provide the Active Directory container relative distinguished name.

For example: CN=Computers

When you run the Add Desktop Pool wizard, you can browse your Active Directory tree for the container.

Allow reuse of pre-existing computer accounts Select this option to use existing computer accounts in Active Directory for linked clones that are provisioned by Horizon Composer. This option lets you control the computer accounts that are created in Active Directory.

When a linked clone is provisioned, if an existing AD computer account name matches the linked clone machine name, Horizon Composer uses the existing computer account. Otherwise, a new computer account is created.

The existing computer accounts must be located in the Active Directory container that you specify with the Active Directory container setting.

When this option is disabled, a new AD computer account is created when Horizon Composer provisions a linked clone. This option is disabled by default.

For details, see "Use Existing Active Directory Computer Accounts for Linked Clones," in the Setting Up Virtual Desktops in Horizon 7 document.

Use QuickPrep or a customization specification (Sysprep) Choose whether to use QuickPrep or select a customization specification (Sysprep) to configure licensing, domain attachment, DHCP settings, and other properties on the machines.

Sysprep is supported for linked clones only on vSphere 4.1 or later software.

After you use QuickPrep or Sysprep when you create a pool, you cannot switch to the other customization method later on, when you create or recompose machines in the pool.

For details, see "Choosing QuickPrep or Sysprep to Customize Linked-Clone Machine," in the Setting Up Virtual Desktops in Horizon 7 document.

Power-off script QuickPrep can run a customization script on linked-clone machines before they are powered off.

Provide the path to the script on the parent virtual machine and the script parameters.

Post-synchronization script QuickPrep can run a customization script on linked-clone machines after they are created, recomposed, and refreshed.

Provide the path to the script on the parent virtual machine and the script parameters.