Duplicati

This review is based on the "experimental" version 2.0.

Duplicati is fantastic software for backing up your files. It works on Mac, Windows and Linux. You select a folder or folders for it to keep and eye on, and corresponding folders where your backed up files should end up. It then asks for a schedule - how often it should look for changes and make a backup. It can listen every six minutes or more. The interface is based in your internet browser, a little bit like SyncThing, but even smoother in the way it works.

Although Duplicati has built in support to talk directly to online Sync/backup services, such as Dropbox, this is a little unnecessary, since you can tell the clients of such services simply to watch out for a particular folder, and you can choose the destination folder discussed above.

More impressive is that Duplicati comes with optional encryption for your files. When choosing the folder the app is watching, you choose also the encryption option and a (hopefully strong) password. With that setup, Duplicati will not only produce a backed up verion of your files, but encrypt them along the way using the very strong AES-256 standard. This way, if the destination folder is being monitored by a backup or sync client (e.g. of Dropbox), only encrypted versions of your files will be put into the cloud. That is very important for maintaining your online privacy, because Dropbox and related services have access to all your files, and have been known to a) get hacked, b) pass on people's info (files included) to law enforcement. Duplicati even hides the size and structure of your files. If you use encryption to backup, say, a 700 Mb file (ahem), the encrypted output from Duplicati will be 14 x 50MB files, which are unreadable to anyone who doesn't have the password. Moreover, to restore a file from backup, you enter the password and it restores the file structure in a menu, so you can pick what you want from all the files you backed up without having to decrypt/restore everything (unless you want to).

The only comparable app to this is Cryptomator, which also encrypts on a file-by-file basis, but is more tuned to syncing than to backups. (Check that out also: it's excellent for protecting your privacy if you're using the Cloud.)

Duplicati is brilliant, and the developer deserves a medal. Or, if you prefer, a donation. It's really a great thing that software this useful is freely available and open source. Highly recommended.

Concerning scheduling, VSS and cleaning up file/folder-backups Duplicati is the best free and portable app for folder-backup-purposes with VSS. For backups of single files I prefer Uranium (portable) or Cobian backup. Uranium Backup has the very important VSS-ability only in the very expensive commercial version, Cobian BU is not portable and is not so good in time-scheduling. But the next Duplicati-version will have a new and better UI, where you can select single files without using regular expressions.
For a good backup functionality it is necessary to cleanup more/older than x backups (CLU) not only older backups than x months, and to configure the schedule of a backup also for each 2nd Monday 10:00 and to pause if the system is busy (Sch).

Comparison of file/folder backup applications:

Comparison ......... CLU . Sch . Language

SyncBack Free...... No ... Yes .. English only

Cobian Backup .... Yes .. No ... Many

Acronis True Im.... Yes .. Yes .. Many

Duplicati ...............Yes .. Yes .. Dan.,En.,Fr.,Germ.,Port.

Areca Backup ..... No .. Yes .. English only

Personal Backup .. No . Yes .. Engl.+German

Saft Backup .........Yes .. No .. Engl.+German

Duplicati is the best free and portable backup application:

Acronis True Image has all necessary functions, has multi-language UI and additionally can do harddisk images with best functions, but it is not free and it is not portable, so you need admin rights to install it.
Both Duplicati and Saft Backup can do backups with Volume Shadow Copy Service (VSS), but Saft Backup cannot do a backup on each second Monday and has no flexible file filter. Cobian Backup is very good, but has the big disadvantage, not to be able to schedule a backup e.g. monthly on each 2nd Tuesday and not to be portable.

This seems very poorly designed.

You can try to backup ~2 TB of data and it says that it needs to backup 600 TB(!), probably from following recursive symlinks or something? There's no obvious way to find out where the links are or how to exclude them.

Or it tells you there's been an error, and when you click "Show" it shows a list of plain text dates that aren't obviously clickable. If you click one, it shows you a dump of json(?) code that means very little. You can search for "error" and try to find the errors that way.

If you've requested a folder to be backed up and the folder is then deleted, Duplicati just stops backing up anything! Your data could very easily be lost.

[Edited by endolith, July 16]

After months of using this, I've lowered my rating to the worst score. It's highly buggy and poorly-written, and there's little helpful support on their forum.

Easy to setup and backup your files with encryption to cloud storage you're already using.

One of the only open source backup programs that supports many cloud storage options, with encryption and incremental backups. It's also managed via WebUI and can be accessed remotely if enabled, and supports email notifications for backups.

The best backup solution for me.

This just doesn't seem to work well at all in windows.

Manually using the command line has problem with source and exclusion paths, and the GUI "command line" section just throws a lot of errors when trying to use the software. After trying to get the settings to actually work for a few hours, I'm giving up.

When running backups, both file collation and copying is ridiculously slow. Like 32KB/s slow when both source and destination are on local hard drives. I think this is because the software is, every time it is ran, checking ALL data in EVERY file for the sector based storage, which must be pretty intensive. While there are probably options to use the different backup types, the options are just not easy to use at all, even in the GUI.

I'm giving this a 3 star because I have a feeling it does some things really well that other people need it for, but not me. It seems to be in a class of its own for certain claimed functionalities. It also probably works a lot better on Linux.