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Virtual SAN does not support the View Composer Array Integration (VAAI) feature because Virtual
SAN does not use NAS devices.
NOTE Virtual SAN is compatible with the View Storage Accelerator feature. Virtual SAN provides a
caching layer on SSD disks, and the View Storage Accelerator feature provides a content-based cache that
reduces IOPS and improves performance during boot storms.
The Virtual SAN feature has the following requirements:
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vSphere 5.5 Update 1 or a later release.
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Appropriate hardware. For example, VMware recommends a 10GB NIC and at least one SSD and one
HDD for each capacity-contributing node. For specifics, see the VMware Compatibility Guide.
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A cluster of at least three ESXi hosts. You need enough ESXi hosts to accommodate your setup. For
more information, see the vSphere Configuration Maximums document, available from
https://www.vmware.com/support/pubs/vsphere-esxi-vcenter-server-pubs.html.
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SSD capacity that is at least 10 percent of HDD capacity.
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Enough HDDs to accommodate your setup. Do not exceed more than 75% utilization on a magnetic
disk.
For more information about Virtual SAN requirements, see "Working with Virtual SAN" in the vSphere
Storage document.
Reducing Storage Requirements with View Composer
Because View Composer creates desktop images that share virtual disks with a base image, you can reduce
the required storage capacity by 50 to 90 percent.
View Composer uses a base image, or parent virtual machine, and creates a pool of up to 2,000 linked-clone
virtual machines. Each linked clone acts like an independent desktop, with a unique host name and IP
address, yet the linked clone requires significantly less storage.
Replica and Linked Clones on the Same Datastore
When you create a linked-clone desktop pool, a full clone is first made from the parent virtual machine. The
full clone, or replica, and the clones linked to it can be placed on the same data store, or LUN (logical unit
number). If necessary, you can use the rebalance feature to move the replica and linked clones from one
LUN to another or to move linked clones to a Virtual SAN datastore or from a Virtual SAN datastore to a
LUN.
Replica and Linked Clones on Different Datastores
Alternatively, you can place View Composer replicas and linked clones on separate datastores with different
performance characteristics. For example, you can store the replica virtual machines on a solid-state drive
(SSD). Solid-state drives have low storage capacity and high read performance, typically supporting tens of
thousands of I/Os per second (IOPS). You can store linked clones on traditional, spinning media-backed
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, you cannot manually select different datastores for replicas and linked
clones. Because Virtual SAN automatically places objects on the appropriate type of disk and caches of all
I/O operations, there is no need to use replica tiering for Virtual SAN datastores.
Chapter 3 Managing Desktop and Application Pools from a Central Location
VMware, Inc. 35