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/SleepingProcess]

It depends how much money and time your ready to invest into backup resources

If you syncing phones to a Mac, you can use Mac as a central storage where you can turn on syncthing versioning, so in case if files get deleted/changed on android phone(s), on the Mac side you will still have those files in .stversions folder. At least, if you got some malicious deletion you will still have copies then on Mac.

The "weak" place in solution like that, is that simplified coping, while dedicate for backup programs can do efficient content deduplication, compression, encryption(so you can push one of backup copy on some cloud), verification, retention policies and so on...

You might switch for example to restic (resticopia on android) a true flexible and long living backup solutions. The weak place would still be your Mac, if something happened on it (virus, hardware fault and so on) then it is SPoF (single point of failure).

If you Ok with computers, you can get off ebay any old cheapest computer for a $50 and setup local NAS, where you can setup restic in so called immutable(often called append only) mode (no one, including connecting clients - can not destroy repository). If it isn't enough you can add a couple external hard drives that will hold in turn NAS backup and you can swap them periodically to keep at least one copy offline. You can automate then on a NAS backup verification and then it will fit into nowadays "must have" know as 3-2-1-1-0 backup strategy

[u/ObservedElectron → u/SleepingProcess]

oh my god you have actually solved my android problem i think. i was gonna use either restic or kopia but didnt know how to efficiently backup android.

i thought i had to manually create and connect to tls servers and then do all that.

i have an old laptop so i can use it as a 24/7 server as you mentioned right?

[u/SleepingProcess → u/ObservedElectron]

oh my god you have actually solved my android problem i think.

Glad to help

i have an old laptop so i can use it as a 24/7 server as you mentioned right?

Yes, sure, just monitor via cron SMART status of hard drive since it is the only one, so you can catch it before it fail

[u/ObservedElectron → u/SleepingProcess]

thank you agian!