Fast Site Collection Creation is a mechanism designed to improve provision performance of Site Collections where provisioning is simply a copy operation which happens at the Content Database level. You can read more about Fast Site Creation here
Firstly, to enable the Fast Site Collection Creation for a template, you would need to run the following PowerShell Command
Enable-SPWebTemplateForSiteMaster -Template “STS#0” -CompatibilityLevel 15
The above command is Template Specific, so you need to run the similar command to enable fast site creation on all those webtemplates that you need to include in the process of fast site collection creation.
Next Create a SiteMaster in one of the Content databases. A SiteMaster is like a empty site collection that preserves the settings (from the template it was created with), that will be needed for the new Site Collection to be created. It preserves the Features to activate on copy of the site collection, template setting etc.
To Create a SiteMaster, you need a Content database and a fast site creation enabled template that it will be created using.
Let’s get the DB where we have already provisioned a site collection.
$DB = Get-SPContentDatabase -site http://sp2016vm:4430/sites/team
Now lets create a SiteMaster in it.
New-SPSiteMaster -ContentDatabase $DB -Template “STS#0”
You can also use Get-SPSiteMaster to confirm if the SiteMaster has been created in a particular database.
Similarly, you can use Remove-SPSiteMaster to remove the SiteMaster from your Content database.
Finally, provision a new site collection using –CreateFromSiteMaster parameter.
New-SPSite http://sp2016vm:4430/sites/FastSite1 -ContentDatabase $DB -CompatibilityLevel 15 -CreateFromSiteMaster -OwnerAlias “sp2016\sp16_farm”
Site Collections are now created by copying at Content Database level with Fast Site Collection Creation enabled. The Feature Activation that usually happens during regular Site Collection creation does not occur.
Here is the Central admin Screenshot of Site Master and the new “FastSite1” Site Collection