5.2

From an architectural perspective, View Composer creates desktop images that share a base image, which can
reduce storage requirements by 50 percent or more. You can further reduce storage requirements by setting a
refresh policy that periodically returns the desktop to its original state and reclaims space that is used to track
changes since the last refresh operation.
If you use View Composer with vSphere 5.1 or later virtual desktops, you can use the space reclamation feature.
With this feature, stale or deleted data within a guest operating system is automatically reclaimed with a wipe
and shrink process when the amount of unused disk space reaches a certain threshold.
You can also reduce operating system disk space by using View Composer persistent disks or a shared file
server as the primary repository for the user profile and user documents. Because View Composer lets you
separate user data from the operating system, you might find that only the persistent disk needs to be backed
up or replicated, which further reduces storage requirements. For more information, see “Reducing Storage
Requirements with View Composer,” on page 29.
NOTE Decisions regarding dedicated storage components can best be made during a pilot phase. The main
consideration is I/Os per second (IOPS). You might experiment with a tiered-storage strategy to maximize
performance and cost savings.
For more information, see the best-practices guide called Storage Considerations for VMware View.
Storage Bandwidth Considerations
In a Horizon View environment, logon storms are the main consideration when determining bandwidth
requirements.
Although many elements are important to designing a storage system that supports a Horizon View
environment, from a server configuration perspective, planning for proper storage bandwidth is essential. You
must also consider the effects of port consolidation hardware.
Horizon View environments can occasionally experience I/O storm loads, during which all virtual machines
undertake an activity at the same time. I/O storms can be triggered by guest-based agents such as antivirus
software or software-update agents. I/O storms can also be triggered by human behavior, such as when all
employees log in at nearly the same time in the morning. VMware has tested a logon storm scenario for 10,000
desktops. For more information, see “View Composer Performance Test Results,” on page 54.
You can minimize these storm workloads through operational best practices, such as staggering updates to
different virtual machines. You can also test various log-off policies during a pilot phase to determine whether
suspending or powering off virtual machines when users log off causes an I/O storm. By storing
View Composer replicas on separate, high-performance datastores, you can speed up intensive, concurrent
read operations to contend with I/O storm loads.
In addition to determining best practices, VMware recommends that you provide bandwidth of 1Gbps per 100
virtual machines, even though average bandwidth might be 10 times less than that. Such conservative planning
guarantees sufficient storage connectivity for peak loads.
Network Bandwidth Considerations
Certain virtual and physical networking components are required to accommodate a typical workload.
For display traffic, many elements can affect network bandwidth, such as protocol used, monitor resolution
and configuration, and the amount of multimedia content in the workload. Concurrent launches of streamed
applications can also cause usage spikes.
Because the effects of these issues can vary widely, many companies monitor bandwidth consumption as part
of a pilot project. As a starting point for a pilot, plan for 150 to 200Kbps of capacity for a typical knowledge
worker.
VMware Horizon View Architecture Planning
52 VMware, Inc.