Everyone has at least some data that is of incalculable value. The best way to safeguard data is through routine, automated backup, including the occasional verification of backups to ensure all the desired files are successfully saved. Herein the installation and usage of the Open Source™ backup application Duplicati is explored.

The Duplicati application is available for Microsoft Windows™ (XP, Vista, 7) systems and is completely free, both in the monetary sense and in the sense that the source code to the application is freely available to anyone that wishes to evaluate or modify it. For most, the former is of most interest. As of this writing, the latest version of Duplicati is 1.2b.

Before installation, a little terminology is in order. For those not familiar with traditional data backups, the two kinds are known as full and incremental. The former is when every file selected for backup is copied to another location. The second, an incremental backup, contains only the files that have been modified since the least full backup was completed. Generally, due the scarcity of disk space and wall clock time (time as it passes in the real world), a full backup will be done every few weeks whereas an incremental can be done more frequently.


The installation process is straightforward. First, download Duplicati. If you are using the Firefox Web browser, the download will usually end up in My Documents\Downloads. Run the downloaded file and click OK if warned about it being an unsigned MSI. Vista and 7 users likely need to allow Duplicati to have administrator success to install files. The explanation of each screen follows the image itself.

The Duplicati Setup Wizard should appear.

To continue, review and accept the LGPL license agreement.

Accept the default installation options.

Click Install to continue the process.

Finally, check Launch Duplicati now and click Finish to begin the Setup Wizard.

Configure a Backup

The application uses a Wizard based interface.

With Setup a new backup selected, click Next. At any time, it is possible to go back by simply clicking Back.

Before configuring the backup, a name must be given to it. In the sample the backup has been named “default”. After typing a name, click Next.

At last, the meat of the application. It is possible to either backup only the Windows' My Documents folder hierarchy or select a Custom folder list. Depending on the software mix you use, you may have data files located in other places. When selecting a custom folder, the button will launch an Explorer instance from which you can navigate to and pick a custom folder. You can backup as many custom folders as you wish. If you make a mistake, the trashcan icon will remove the adjacent custom folder.

To protect your privacy, it is possible – and the default in Duplicati – to encrypt your backup data. You can either enter a password of your choosing or allow Duplicati to generate one for you. Be forewarned, the generated passwords are quite secure. Therefore, you may make a mistake when writing it down. If you loose or misprint the password, it is impossible for you to recover data from your backup!

One of the spectacular things about Duplicati is its support for a wide variety of storage mediums. Unless you recognize most of the selections, you will want to select the File based choice. That will enable you to store your backups in a variety of traditional places, including an external USB hard drive or thumb drive. If you have neither, rest assured you can store your backups on your local computer hard disk. However, your data will not be protected against catastrophic hardware failure, so the local disk should be your last choice. It is possible to burn backups to optical media, such as DVD or BluRay, but that is beyond the scope of this document.

A further note about backup storage choices. Ideally, you want to store your backups someplace else. Preferably at another physical location. (That's where the other storage choices, FTP, SSH, Amazon S3, and others come in.) While USB thumb drives are popular and inexpensive, overtime they are prone to wear. Solid state memory support a fixed number of write cycles after which they die. If it's within your budget, a USB hard disk is a better choice, provided it is the smaller 2.5” form factor, such as in the Western Digital My Passport USB drive or similar competitor offerings.

Click Next to be asked where on the File based storage to write your backups. Duplicati will attempt to automatically detect USB storage media or you can select a Path manually. If you are using a dedicated drive for backups, which you should, the root path (i.e. E:\) is fine. Click Next to proceed.

Of the Advanced settings, the most fruitful is to Select when and how often the backup should run. Click Next to explore when and how often.

By default, Duplicati performs backups daily at 1:00 P.M. in your timezone. Monthly it will perform a full backup, discussed earlier. Every subsequent backup will be incremental. These defaults are fine for most users. Click Next to be nearly finished.

Review the summary and optionally select Run backup now to start your first full backup. If you have a ton of data you may wish to defer. The automatic, nightly backup will still run.

Performing a Restore

Naturally, there is little purpose to performing backups that cannot later be restored. The restore process for Duplicati is also wizard based.

First, find the Duplicati icon in the system tray and right click on it. From the menu, choose Wizard… Alternately, the Duplicati wizard can be started by running it from its Start menu entry.

Next, select Restore files from a backup and then click Next.

Choose the name of the backup you wish to restore from. You can configure many different named backups, so there may be more than one in the list. Click Next.

A list is presented with the dates and times of backups that have run. Select the one closest to when the file you seek was last modified or deleted. (You can repeat the restore process until you find the version of the file you want if you are unsure of the date.) Click Next.

The file or the entire backup can be restored anywhere on your hard disk or alternate removable storage. Click the to expand the Browse for Folder window. From that window, you have access to all your lettered disk drives, just as in My Computer for Windows XP or Computer for Windows Vista. In the example, a new folder named “my_restore” is created to hold the backups. You will need enough free space for the files you restore.

If Restore only the items selected below is checked, the window changes to allow you to select one or more files or entire directories to restore. Only the selected files are restored. Otherwise, the entire backup is restored. Click Next to proceed.

Finally, it's time to restore the required data. Click Finish and the Duplicati will begin the process. Open Windows Explorer and navigate to the directory created earlier to find the restored data. In the example, the Duplicati installer was restored from the backup. Success!

guide/duplicati.txt · Last modified: 2011/04/08 17:11 by jasonb
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