I've been using Kopia for my personal use and for products I have helped build at a couple of enterprise backup companies! It's also used by other open-source backup projects that focus on specific ecosystems (Velero and Kanister for Kubernetes, Corso for Microsoft 365 backup).
I am obviously biased but it's pretty amazing. AMA.
Do you (sorry, but just checking) repeatedly test backups? Eg pull monthly and bit verify that they're correct? Are you aware of anyone testing in this way?
I can only compare it from a user experience point of view. I tried duplicati for my windows laptop and was never quite happy. Kopia just worked from day one. The front-end still has a few bugs here and there particularly if you on windows electron eating sockets, WebDAV mounts not always working), however the backend seems very reliable (only did one full restore, but I also did not note any reports).
It still has a lot of potential, IMHO. You e.g. find some hints how to use it with AWS storage tiering in the docs.
I haven't looked at duplicati in a while and, it has evolved. While Duplicati's feature set looks similar now, I would need to benchmark it both for efficiency and final backup sizes.
And, while not directly, I know a number of companies, including mine, do test restores all the time.
Not the previous poster, and I don't use Kopia, but after reading Kopia features and docs, they seem to be in par. I use Duplicati quite extensively for personal backups, and didn't really have any issues.
Duplicati has a web interface, so with a proper authentication in place, you can use it to remotely monitor and manage backups.
Duplicati doesn't keep a local cache. It uses SQLite files for file meta data, but not for the content themselves.
I like Duplicati's snapshotting mechanism. You can specify how long or how many snapshots to keep, and my anecdotal evidence is that it's archival storage-friendly. I imagine S3 and it's lifetime management rules can bring a decent and cost effective backup solution.
I'm using Google Drive 2TB plan, and I didn't see Kopia supporting Google drive out of the box.
Hmm. I'm asking because I've had some trouble with Duplicati. I use it on a laptop, and it does not like being interrupted during a backup. It also doesn't fail the backup, which would be fine; instead, it gets jammed on files, particularly the large (multigb sqlite) file it generates to track state. It remains jammed, even once network is restored, and measures upload speeds at single-digit bytes per second. I end up having to force kill it after multiple abort requests fail to stop the jammed backup, and there's multiple warnings that this can corrupt data / you shouldn't kill the process...
So anyway, I'm looking for alternatives.
Duplicati also, somewhat annoyingly, nails 100% cpu for a while during backup which spins up the fans and gets my laptop very hot. I've been meaning to see if there's a simple way to modify the code to prevent this, but I'm very unfamiliar with C#.
I am obviously biased but it's pretty amazing. AMA.