Non-Timed Incremental Backup between 2 NAS over the Internet

[linyingyen]

I live in two countries with a NAS at each location.

I want to do incremental backup from NAS-A to NAS-B over the internet (don't transfer what NAS-B already has)

Then go use NAS-B for another few months on LAN, change its files, then do incremental backup to NAS-A over the internet (again, not transfer anything that NAS-A already has.)

I don't want them to sync. I only want one to backup to another when I tell it to. Probabaly the morning of my flight back to the other country.

Is this possible? Thanks in advance!

[dolbyman]

a non scheduled nas to nas rsync should do that .. just create a job and run it as needed

[linyingyen]

a non scheduled nas to nas rsync should do that .. just create a job and run it as needed

Sorry if this is a dumb question.

I understand with rsync when NAS-A backup to NAS-B it will compare NAS-A CURRENT-FILES to NAS-A BACKUP-FILES on NAS-B, and only copy the changes.

However, when Months later I backup NAS-B to NAS-A, will it compare NAS-B CURRENT-FILES to NAS-A CURRENT-FILE? Because NAS-A's current files weren't created by rsync, can it compare and only copy the changes?

If not, and it copy the all the files file, then it changes all the file on NAS-A and next time NAS-A will backup all the files to NAS-B again thinking they were all changed.

[linyingyen]

Also, rsync only works one-way.

Does this mean I should setup a rsync job for A->B on NAS-A.
And another rsync job for B->A on NAS-B?

And both will compare their current files to the other NAS's current files?
Even if to that NAS it is doing that rsync job for the very first time?

Thanks!

[dolbyman]

Here is how rsync works
https://en.wikipedia.org/wiki/Rsync

A job as you describe it A->B and then A<-B on the other NAS seems fine to me. Replicate in the direction you want it.

[linyingyen]

Here is how rsync works
https://en.wikipedia.org/wiki/Rsync

A job as you describe it A->B and then A<-B on the other NAS seems fine to me. Replicate in the direction you want it.

Thanks!

One last question,
After A->B, when I start B->A, B will see that there is a folder with the same name on A even though it has never done a B->A sync before. On Synology NAS it will create another folder instead of sync over the existing folder on A. So the method we talked about wouldn't work on Synology. But it will work and sync over existing folder on Qnap?

Again, thanks!

[P3R]

After A->B, when I start B->A, B will see that there is a folder with the same name on A even though it has never done a B->A sync before.

The job will take longer the first time as nothing is cached but yes, rsync always compare source with destination and copies the differences as configured.

But it will work and sync over existing folder on Qnap?

Yes when using Backup Station, NAS to NAS (which is rsync when used between two Qnaps) and having correctly configured the same (but opposite) source and destination folders in the backup job of each NAS.