Setting Up Desktop and Application Pools in View

datastores. These disks provide lower performance, but are less expensive and provide higher storage
capacity, which makes them suited for storing the many linked clones in a large pool. Tiered storage
configurations can be used to cost-effectively handle intensive I/O scenarios such as simultaneous rebooting
of many virtual machines or running scheduled antivirus scans.
For more information, see the best-practices guide called Storage Considerations for VMware View.
If you use Virtual SAN datastores or Virtual Volumes datastores, you cannot manually select different
datastores for replicas and linked clones. Because the Virtual SAN and Virtual Volumes features
automatically place objects on the appropriate type of disk and cache of all I/O operations, there is no need
to use replica tiering for Virtual SAN and Virtual Volumes datastores.
Disposable Disks for Paging and Temp Files
When you create a linked-clone pool, you can also optionally configure a separate, disposable virtual disk to
store the guest operating system's paging and temp files that are generated during user sessions. When the
virtual machine is powered off, the disposable disk is deleted. Using disposable disks can save storage space
by slowing the growth of linked clones and reducing the space used by powered off virtual machines.
Persistent Disks for Dedicated Desktops
When you create dedicated-assignment desktop pools, View Composer can also optionally create a separate
persistent virtual disk for each virtual desktop. The end user's Windows profile and application data are
saved on the persistent disk. When a linked clone is refreshed, recomposed, or rebalanced, the contents of
the persistent virtual disk are preserved. VMware recommends that you keep View Composer persistent
disks on a separate datastore. You can then back up the whole LUN that holds persistent disks.
Storage Sizing for Linked-Clone Desktop Pools
View provides high-level guidelines that can help you determine how much storage a linked-clone desktop
pool requires. A table in the Add Desktop Pool wizard shows a general estimate of the linked-clone disks'
storage requirements when the pool is created and as the linked clones grow over time.
The storage-sizing table also displays the free space on the datastores that you select for storing OS disks,
View Composer persistent disks, and replicas. You can decide which datastores to use by comparing the
actual free space with the estimated requirements for the linked-clone disks.
The formulas that View uses can only provide a general estimate of storage use. Your linked clones' actual
storage growth depends on many factors:
n
Amount of memory assigned to the parent virtual machine
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Frequency of refresh operations
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Size of the guest operating system's paging file
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Whether you redirect paging and temp files to a separate disk
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Whether you configure separate View Composer persistent disks
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Workload on the linked-clone 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 linked clones, configure your linked-clone
pools 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 linked-clone 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 View Architecture Planning document.
Chapter 15 Reducing and Managing Storage Requirements
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