Architecture Planning

Table Of Contents
For 10,000 desktops the logon storm occurred over a 60-minute period, using a normal distribution of logon
times. The virtual machines were powered on and were available before the logon storm began. After logon,
a workload started, which included the following applications: Adobe Reader, Microsoft Outlook, Internet
Explorer, Microsoft Word, and Notepad.
Following are additional details of the logon storm that was sustained during testing:
n
95% of logons occurred within +/- 2 standard deviation window (40 minutes).
n
68% of logons occurred within +/- 1 standard deviation window (20 minutes).
n
Peak logon rate was 400/min, or 6.67/second.
Time Required for Provisioning a Pool
Pools are provisioned either up front, when you create the pool, or on demand, as users are assigned to
them. Provisioning means creating the virtual machine and configuring it to use the correct operating
system image and network settings.
In a test setup already containing 4 pools of 2,000 virtual machines in each pool, provisioning a fifth pool
that contained 2,000 virtual machines took 4 hours. All virtual machines were provisioned up front.
Time Required for Recomposing a Pool
You can use a recompose operation to provide operating system patches, install or update applications, or
modify the desktop hardware settings of virtual machines in a pool. Before recomposing a pool, you take a
snapshot of a virtual machine that has new configuration. The recompose operation uses that snapshot to
update all virtual machines in the pool.
In a test setup of 5 pools of 2,000 virtual machines in each pool, a recompose of one pool of 2,000 virtual
machines took 6 hours and 40 minutes. All virtual machines were powered on and available before the
recompose operation began.
Time Required for Refreshing a Pool
Because disks grow over time, you can conserve disk space by refreshing a desktop to its original state when
users log off, or you can set a schedule for periodically refreshing desktops. For example, you can schedule
desktops to refresh daily, weekly, or monthly.
In a test setup of 5 pools of 2,000 virtual machines in each pool, a refresh of one pool of 2,000 virtual
machines took 2 hours and 40 minutes. All virtual machines were powered on and available before the
refresh operation began.
Time Required for Rebalancing a Pool
A desktop rebalance operation evenly redistributes linked-clone desktops among available logical drives. A
rebalance operation saves storage space on overloaded drives and ensures that no drives are underused.
You can also use a rebalance operation to migrate all virtual machines in a desktop pool to or from a Virtual
SAN datastore.
In a test pod that contained 5 pools of 2,000 virtual machines in each pool, 2 datastores were added to the
pod for one test. For another test, 2 datastores were removed from the pod. After the datastores were added
or removed, a rebalance operation was performed on one of the pools. A rebalance of one pool of 2,000
virtual machines took 9 hours. All virtual machines were powered on and available before the rebalance
operation began.
Chapter 4 Architecture Design Elements and Planning Guidelines for Remote Desktop Deployments
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