Microsoft

Use Robocopy's multi-threaded feature to quickly back up your data in Windows 7

Greg Shultz shows you how to take advantage of Robocopy's multi-threaded copy feature to create an exact mirrored duplicate of your user profile folder.

Soon after Windows Vista came out, I discovered that Microsoft had updated the venerable Robocopy with a bunch of extra features and made it a regular part of the Windows operating system. Of course, when Windows 7 came out I immediately examined the newest version of Robocopy and discovered that Microsoft had again updated Robocopy with a single, but very powerful, new feature — the ability to perform a multi-threaded copy option. More specifically, with multi-threaded capabilities Robocopy can now simultaneously copy multiple files in parallel, which will result in very fast backup operations.

In this edition of the Windows Desktop Report, I'll show you how to take advantage of Robocopy's features to create an exact mirrored duplicate of all the pertinent data files in your user profile folder (C:\Users\YourName). As I do, I'll show you how to use the new multi-threaded copy feature.

This blog post is also available in PDF format in a TechRepublic download.

Why use Robocopy?

If you're conscientious about the safety of your data, chances are good that you are already using Windows 7's Backup and Restore tool to create an image file of your hard disk as well as to back up your data files on a regular schedule. However, you may like to have an additional copy of your data files just to be on the safe side. While you can easily do so by copying your files and folders to an external hard drive via drag and drop, that can be a tedious operation.

Fortunately, Robocopy provides more than 80 different command-line switches that will allow you to create a powerful data backup operation. To help you get a leg up, I have delved into Robocopy 's command-line switches and have developed a nice little script that you can use to create an exact mirrored duplicate of all the data files in your user profile folder (C:\Users\YourName). Let's take a closer look.

Constructing the command line

For my example, I'm going to back up the data file contents of my user profile folder, C:\Users\Greg Shultz, to a folder named TheBackup on an external hard disk that is assigned drive letter G. (You'll, of course, substitute the names and paths with your own.) As such, my command will begin with:

Robocopy "C:\Users\Greg Shultz" "G:\TheBackup"

Now, I want to back up every folder in the source, even any empty folders, as they may be placeholders for future data. I also don't want to have files on the backup that I deleted from my hard disk. While I can use the /S and /PURGE switches to accomplish my goal, I can use the /MIR switch to accomplish both of these tasks with one switch. As such, my command is now:

Robocopy "C:\Users\Greg Shultz" "G:\TheBackup" /MIR

The C:\Users\Greg Shultz folder contains several hidden, system files and folders that I don't want or need to back up. For example, I don't need to back up the NTUSER.DAT file nor do I need to back up the contents of the AppData folder. In addition, the C:\Users\Greg Shultz folder contains a host of junction points that I don't need to back up.

Windows 7 uses junction points to link various operating system folders to the user profile folder. For example, the Cookies folder and the SendTo folder are linked to the user profile folder via junction points.

I'll use the /XA:SH switch to exclude the hidden, system files, and I can use the /XD AppData to exclude the entire AppData folder. I'll then use the /XJD to exclude all the junction points. As such, my command is now:

Robocopy "C:\Users\Greg Shultz" "G:\TheBackup" /MIR /XA:SH /XD AppData /XJD

One of Robocopy's most useful features comes in to play when it encounters a file that is in use. When it does, Robocopy will stop and wait for that file to close so that it can continue with the copy operation. It will retry to copy the file every 30 seconds. The default number of retries is one million (no joke!). As this will most like prevent the backup operation from ever completing, you should reset it to a reasonable number.

To change the number of retries, you'll use the /R switch, and to change the wait time between retries, you'll use the /W switch. I chose 5 retries with a 15-second wait time. That way after a reasonable number of retries and wait period, Robocopy will move on. As such, my command is now:

Robocopy "C:\Users\Greg Shultz" "G:\TheBackup" /MIR /XA:SH /XD AppData /XJD /R:5 /W:15

At this point, I am ready to add the new multi-threaded switch: /MT[:n], where n is a number from 1 to 128 and indicates the number of threads to be used. Keep in mind that n is optional and that by default, the /MT switch will use 8 threads. I'll use 32 threads in my example, as I found it to be a good starting point. (Note that the multi-threaded option is not compatible with the /IPG and /EFSRAW switches.) At this point, my command is now:

Robocopy "C:\Users\Greg Shultz" "G:\TheBackup" /MIR /XA:SH /XD AppData /XJD /R:5 /W:15 /MT:32

Like all command-line tools, Robocopy keeps you apprised of the status of the operation right in the Command Prompt window. However, chances are that you'll want to customize and record that feedback in a log file. I like to have the whole picture, so I'll use the /V switch. However, I really don't need to know the percentage progress of each file copy, so I'll use the /NP switch. To create my log file, I'll use the /LOG switch, which will overwrite the existing log file each time. Now, my command is:

Robocopy "C:\Users\Greg Shultz" "G:\TheBackup" /MIR /XA:SH /XD AppData /XJD /R:5 /W:15 /MT:32 /V /NP /LOG:Backup.log

Creating and using your script

Now that you know how the script works and the necessary switches, you can launch Notepad, type the command, and save the file as RobocopyBackup.cmd. To make sure that the script and open log file don't interfere with the backup, I created a folder in the root directory called BackupTool (C:\BackupTool) and saved the script there.

You'll find the log file in the same directory as the script after each backup operation. Keep in mind that while the log file is a simple text file, it can be larger than Notepad can handle. As such, you may want to use Wordpad or another word processor to open and view the log file.

Now, anytime that you want to make an extra backup, you can just double-click on the RobocopyBackup.cmd to launch it. When it is done, you can examine the Backup.log file. You can also use the Task Scheduler to automatically run your RobocopyBackup.cmd on a regular basis if you want.

What's your take?

Have you used Windows 7's version of Robocopy? If so, what's been your experience? Would you add any additional switches to the script that I presented? As always, if you have comments or information to share about this topic, please take a moment to drop by the TechRepublic Community Forums and let us hear from you.

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About

Greg Shultz is a freelance Technical Writer. Previously, he has worked as Documentation Specialist in the software industry, a Technical Support Specialist in educational industry, and a Technical Journalist in the computer publishing industry.

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