How does Duplicacy compare to Arq and qBackup?



Can you outline advantages if your software over Arq and qBackup: qBackup - Cloud Backup Software?


How Duplicacy compares to other backup solutions

Our biggest advantage over Arq, or any other backup software, is the ability to take advantage of cross-computer deduplication. If you have many computers sharing a similar set of files (such as a large code base) then with Duplicacy these computers can back up to the same storage folder – deduplication occurs across computers. With Arq you’ll have to use a separate storage folder for each computer.

Duplicacy also supports more cloud storages than Arq, the most notable being Backblaze B2.
[Edit 04/28/2019: Arq does support B2 now.]

qBackup seems to be quite primitive at this moment and lacks many features (for instance, no built-in scheduler). They don’t provide any documentation on how their deduplication works so I can’t comment on this aspect.


Thanks. I just ran a test with Duplicacy, and while the backup was indexing the drive, I was seeing hundreds of these messages.

14:51:10.887 Failed to read the symlink: The system cannot find the file specified.


Is this on Windows? Can you run Duplicacy as administrator to see if this is a permission issue.

Unfortunately this log message doesn’t include the file path. I’ll fix it in the next update.


Yes, on Windows 2012 R2 and running as Admin. But, I’m also using Windows native dedup at the drive level so wondering if something odd is happening there.


I see. Each deduped file is actually a reparse point, but Duplicacy can only handle reparse points that are a symlink or a mount point. For others it returns ENOENT.

I think the solution is to treat dedup reparse points as if they are regular files. I’ll fix it.


Thanks. BTW - if you install and text qBackup, I think you’ll find the interface to be slicker than Duplicacy. And there can be multiple jobs. Schedule is done via command line and task scheduler so seems to work fine. I don’t work for this company, but I’ve been testing it and others.



Version 1.2.1 fixed this deduplication reparse point issue.

As for our GUI, we have a different design rationale – we wanted to have a simple configuration page that does most basic things. For advanced users there is a CLI version that is more powerful and more flexible.

split this topic #9

3 posts were split to a new topic: How Duplicacy compares to other backup solutions


I trialed both Arq & Duplicacy. The biggest difference I see is:

  • arq has a much nicer GUI
  • duplicacy has wildly faster backups


Ok, let’s open this can of worms:


  • Massive amount of UI bugs. Moving around windows causes reproducible UI corruption. Reported to Arq a year ago with screencasts and repro steps. Still not fixed.
  • Adding even one regex drastically increases scan time. 700k files takes days to scan. Reported to Arq a year ago. Still not fixed. They recommended using folder exclusions in the tree, which is not sustainable.
  • Without regex the scan time is still very long. They offered test case of 1 million files (1000 folders with 1000 files each ) that in their tests takes under 2 min to scan. On all my Macs scan took 4 DAYS. yes. DAYS. Reported to Arq 8 month ago. Got response “I’m working on making it faster.” Nothing changed by today.
  • Searching for a file. CPU usage 100% for 10+ minutes, after which I give up. Crashplan (Even Crashplan!) accomplishes the same search in 2 min. Lookin at spindump the software keeps repeatedly reallocating small amounts of memory. That’s what takes 99% of CPU. Who designed that? Are they aware of profilers? Blows my mind.
  • That thing costs $50. And I could not even make it work. Pathetic.I kept quiet for a year - giving them a chance to fix it. but the same bugs are still there. I’d stay away. If they can’t fix user-facing issues, how can I trust them not to mess up my backup?

Sorry for harshness, even thinking about this $50 piece of turd makes me mad.

Now qQbackup:

Nice clean UI, but:

  • only supports incremental backups. Hence long chain susceptible to corruption
  • Does not support VSS. So unusable for all practical purposes on Windows


Yes, Duplicacy is absolutely the best (I have also tested many including Arq).

But, Duplicacy needs a better GUI (yes, I purchased it).


This is not true. Arq has supported Backblaze for quite awhile now. I believe just before, and hence after, Backblaze toasted all their personal plan users. I personally use the SFTP option, but the third option down is Backblaze. For reference, here is a list of all destinations supported by the current version of Arq:



Not sure if you realized, but you’re replying to a 2 year old post.


Just wanted to set the record straight.


Arq’s support for B2 was added after the original post was written. I’ve edited the post to cross out that line.


Have you tried the web ui?