Administration

As a best practice, you can conduct a pilot phase to determine the correct value for this setting.
For planning guidelines, see "Architecture Design Elements and Planning Guidelines" in the
Horizon 7 Architecture Planning document.
The required number of concurrent power operations is based on the peak rate at which desktops
are powered on and the amount of time it takes for the desktop to power on, boot, and become
available for connection. In general, the recommended power operations limit is the total time it
takes for the desktop to start multiplied by the peak power-on rate.
For example, the average desktop takes two to three minutes to start. Therefore, the concurrent
power operations limit should be 3 times the peak power-on rate. The default setting of 50 is
expected to support a peak power-on rate of 16 desktops per minute.
The system waits a maximum of five minutes for a desktop to start. If the start time takes longer,
other errors are likely to occur. To be conservative, you can set a concurrent power operations
limit of 5 times the peak power-on rate. With a conservative approach, the default setting of 50
supports a peak power-on rate of 10 desktops per minute.
Logons, and therefore desktop power on operations, typically occur in a normally distributed
manner over a certain time window. You can approximate the peak power-on rate by assuming
that it occurs in the middle of the time window, during which about 40% of the power-on
operations occur in 1/6th of the time window. For example, if users log on between 8:00 AM and
9:00 AM, the time window is one hour, and 40% of the logons occur in the 10 minutes between
8:25 AM and 8:35 AM. If there are 2,000 users, 20% of whom have their desktops powered off,
then 40% of the 400 desktop power-on operations occur in those 10 minutes. The peak power-on
rate is 16 desktops per minute.
Accept the Thumbprint of a Default TLS Certificate
When you add vCenter Server instances to VMware Horizon, you must ensure that the TLS
certificates that are used for vCenter Server are valid and trusted by Connection Server. If the
default certificates that are installed with vCenter Server are still in place, you must determine
whether to accept these certificates' thumbprints.
If a vCenter Server is configured with a certificate that is signed by a CA, and the root certificate
is trusted by Connection Server, you do not have to accept the certificate thumbprint. No action is
required.
If you replace a default certificate with a certificate that is signed by a CA, but Connection
Server does not trust the root certificate, you must determine whether to accept the certificate
thumbprint. A thumbprint is a cryptographic hash of a certificate. The thumbprint is used to
quickly determine if a presented certificate is the same as another certificate, such as the
certificate that was accepted previously.
For details about configuring TLS certificates, see "Configuring TLS Certificates for VMware
Horizon Servers" in the Horizon 7 Installation document.
You first add vCenter Server in Horizon Console by using the Add vCenter Server wizard. If a
certificate is untrusted and you do not accept the thumbprint, you cannot add vCenter Server.
Horizon 7 Administration
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