Syncing two NAS


I have question how to best solve backup situation.
I have Machine at work and in home.
At both places I have local NAS where I do backup.
But if either NAS fail I lost backup in that place.
So I want to somehow duplicate backup from work to home NAS and home backup to work NAS
and got redundancy here.

A lot of files (but not all) are the same as work and home computers are synchronized with syncthing.

What approach should take?


If you have many redundant files, backing them up into a single repository makes sense because then deduplication saves a lot of space. You could rsync the restic repository to the opposite NAS right after you make a new backup to one of them.

Alternatively, you could just always backup to one place and then sync to the other place via rsync if you can make one of the NAS available in both places (e.g. via VPN).

Right now I have Local backups on both machines. And a lot of data is same on both machines. So if I rsync NAS1 to NAS2 and back I will have 200% data usage and I don’t like that. VPN is not available right now.

I just wonder what what approach is better.
To do work backup to NAS1 and do home backup to NAS1 then rsync to NAS2
Or Do work backup to NAS1 and NAS2 and same for home backup (to do backup twice to different repo)
The other option seems even better as I can do at least one backup if network is not available, but is probably a lot slower. …and need something like VPN or similar.

I guess it doesn’t matter, which way you choose but rsyncing from NAS1 to NAS2 can be done in the background, so it’s probably more comfortable. And of course I meant you would have to unify the two backups before you can do that.

If you initialize the two repositories with the same chunker parameters then you could use the new restic copy command in restic 0.10.0 to copy snapshots from one repository to another. Using the same chunker parameters means that snapshots copied can be effectively deduplicated against existing data.

If you run restic copy on both ends you can sync snapshots in both directions. Then you’ll have two different repos containing the same data.

Keep in mind that synchronizing/merging these two repositories can also decrease redundancy: Imagine a destructive event on repo A that propagates to repo B.

IMHO restic copy is a good middle ground that should avoid some of the failure modes other approaches (such as syncrhing) are prone to.

If I use restic copy to other NAS then manual say that all data need to be transfered. And in case of network blackout I can’t make backup from one location.

So for that case seems to be beeter and more secure if I at home issue restic backup for each NAS separately. Even in network blackout the backup is possible to at least one NAS

So what downsides have that scenario:

HomeComputer ---------- LAN-NAS1
HomeComputer ----------WAN-NAS2

WorkComputer -----------LAN-NAS2
WorkComputer -----------WAN-NAS1

If WAN dies the only 1 NAS have snapshot but next backup when WAN works will be done. (but there will be one snapshot les on drive)
If one of NAS dies the other have complete backup for both side.

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