Microsoft disabled short filenaming (8.3) by default starting with Windows 8 / Server 2012. However, this week I ran into a situation where we were unable to write files to a folder that already contained 2.2 million files on a 2008 server. It is easy to argue that a software design that dumps millions of files into a single folder is flawed, sometimes we find ourselves in situations that we cannot fix with design at the time. I attempted to defrag the folder and MFT with contig.exe, without success. A chkdsk didn't help, so I began moving the files to a new folder. This went very fast, but once I got near 1 million files, it slowed to around 6,000 files per hour. I tried robocopy, move, PowerShell's move-item, and nothing was making it any faster.
I found some references to disabling 8.3 short file names (https://support.microsoft.com/en-us/kb/121007), and gave it a shot. This was a 2008 server, and not 2008 R2, so I couldn't take advantage of the fsutil command, even though it references that Operating System in the article. I used this article (https://technet.microsoft.com/en-us/library/cc778996.aspx) to manually set the registry entry for NtfsDisable8dot3NameCreation to 3. After a reboot, the move went from 6,000 files per hour, to 1 million files in 30 minutes!
So if you do not have a need for short filenames on your servers where you have a large number of files (more than 30,000) in a single folder, I highly recommend revisiting this old subject and making a switch. If you can use 2008 R2's fsutil to execute the strip command and remove the short filenames, even better. If you are on a 2008 or prior server, then moving the files to a different directory, should be sufficient to remove the short filenames, then rename that directory to match the old name.
