Fun with FSUtil.exe

While listening to the latest installment of RunAs Radio, I just rediscovered a slick little utility over the weekend called FSUtil.exe that lives on your Windows machine.

Sometimes I have to build a web form that includes a file upload behavior or I’ll want to test the data transfer speed with a specific file size. The FSUtil.exe program can create a file with an exact size super quick.

The following command creates a file that’s exactly 1000 bytes long. I can make it as big as I like. Of course, the file contents are not very interesting, but it does allow me to be specific as far as size.

This program can also improve my system performance when a solution includes a large number of files in a given directory. When there are more than 300,000 files in a directory, you can tell Windows that it doesn’t need to make the 16-bit compatible filename.

Remember, when you create a file with a name like “this-is-my-long-file.xlsx”, Windows creates a duplicate name behind the scenes that has just eight characters in order to allow 16-bit programs access to the file. When you shut this off at the file volume level, Windows has a less work to do, so you get the performance boost if you’re willing to give up access for old programs.

The other related setting will disable the last access timestamp field. Again, if you’re willing to give up a little bit of meta-data on your files, you can get a performance boost here too.