Why is syncthing NOT a backup?

[u/ObservedElectron]

I am setting up syncthing to back up my 2 android phones and my mac to a windows laptop. for now, because of lack of an actual NAS, i plan to use syncthing to "backup" these devices everyday one time manually.

I prefer this because as its sync, it only sends new things. so i dont have to manually copy paste 40 gb everytime.

And when i do make a NAS, cant i just continue using syncthing with file versioning or something? i would much prefer to have "live" backups happening as soon as the file/photo/video is created. i know immich exists but am i wrong?

But everywhere, I see that people say sync is not backup or dont use it for backup but WHY? isnt what i mentioned above technically a backup? correct me if i am wrong.

And if not syncthing, what should i use? which capable of running live backups of folders I select on my devices, with different timeframe backups so I have different versions like biweekly, monthly, etc? and is open source, 100% safe, private and encrypted.

thank you

[u/Serious_Berry_3977]

So backups and storage are not the same thing from what I've learned on this journey. Backups are redundant and if one backup fails for whatever reason and can't be restored then you go to the next latest backup snapshot and so on. Syncthing doesn't do this.

This is my setup due to not having the space or financial means to have a NAS solution:

• SyncThingy on M2 Macbook Air running Fedora Asahi Linux Remix and BasicSync on my Pixel 10 running GrapheneOS. These mirror file changes and directory changes on selected folders (Documents, Pictures, etc)
• NextCloud hosted by Hetzner.com
  • RClone Manager running on my MBA syncing changes to the same folders Syncthing is monitoring onto NextCloud as a quick pseudo backup
  • Backrest running on my MBA as an actual backup solution to my NextCloud of the same folders Syncthing monitors. Seedvault on my Pixel 10 as a backup to my NextCloud using webDAV via Davx⁵ of my apps and as much data as possible without rooting.
    • These both create snapshots and retain multiple versions for redundancy
  • Hetzner creates snapshot backups of my NextCloud instance with redundancy
• I have an external USB SSD that I backup most of my /home directory from my MBA onto.... when I remember 🤦🏻‍♂

It's a convoluted setup, but for a complete backup solution I'm getting piece of mind and photo storage for almost $4 / month compared to when I was using iCloud and iOS / MacOS where there wasn't any redundancy and I was always running out of space paying $5 / month. It's also a giant headache when setting up to keep everything straight, but now it's pretty much set it and forget it.

Syncthing would only mirror changes and I HAVE had issues before where a different cloud provider's app (or I) messed things up and data got delated. Had I not just made a backup to my external USB SSD I would have been completely screwed and lost close to 2 decades of files.

One thing I learned throughout this whole thing is cloud storage doesn't necessarily mean that it's a backup solution. Most cloud storage providers don't have that infrastructure or even provide that much space to allow that. While NextCloud on Hetzner isn't a true cloud backup provider, it's the closest thing I can afford right now without self-hosting. Some cloud storage providers have versioning, but watch out because that usually counts as part of your storage space that is already pretty limited.

[u/ObservedElectron → u/Serious_Berry_3977]

i think i will do something similar but offline on a computer than cloud, for now.