How create a file with 1 GB of data using the command line in Windows Server 2019, you can use the fsutil command. Here’s an example:

1fsutil file createnew filename.txt 1073741824

In this command, filename.txt is the name of the file you want to create and 1073741824 is the size of the file in bytes (1 GB).

Note that this command will create a file filled with zeros, which may not be useful for your purposes. You can change the contents of the file using a text editor or other tools.