How to Copy all the site collections from one web application to another?

Question

I have an two web-applications. https://source.company.com and https://destination.company.com. I want to make a copy of the site collection from source to destination within the same farm.

On source, I have two site collections - sourcecollection1 and sourcecollection2. These have a lot of documents, libraries and document collections. Many of the artifacts are attached to item IDs and several documents have versioning associated to them. I need them intact and match on the destination as well. ShareGate doesn't allow this even with INSANE MODE as it is On-Premise. Can anyone help me with this? A Powershell Script of a C# console application would be very helpful.

Thanks.

Answer 1

You would need to use Backup-SPSite and Restore-SPSite. This will bring the site over with full fidelity while changing the Site.ID value (must be unique per farm).