I had to search around again for how to create a large file for testing; time for a blog post.
When you need to work with a large file for testing, fsutil.exe (baked into Windows) has a cool feature for making a large file in a snap. This is useful for when you test your app’s ability to move and edit local files or simply upload a big document.
Here’s the command for creating a 20MB file:
fsutil file createnew c:\temp\largefile.txt 20000000