Remote Syncing RSnapshots

Question

I am in the process of setting up a (proper) backup system which is built upon my NAS and rsnapshot. I have the NAS which has two drives in case one dies which in itself is not a backup, but I am also taking daily, weekly and monthly rsnapshots of the NAS which is being stored onto an external HDD.

I want to have an external off-site copy of this data, and trying to work out the best way to do this. I know you can't remote rsnapshot, but is it better to sync the rsnapshot directory which contains the daily / weekly / monthly snapshots, or would it be better to do an rsync of all of the files i would backup on my local NAS to a remote NAS, and then rsnapshot the remote NAS directory.

Apologies if this is convoluted, I am just trying to work out which would save more bandwidth, to rsnapshot the local NAS, save it on the external HDD and then rsync the external HDD to the remote nas, or to rsync everything on the local NAS to the remote NAS, and then rsnapshot the remote NAS?

My worry is that given everything would likely change in the local rsnapshot directory, e.g. daily.0 becoming daily.1, would this mean the entire backup needs to be sync'd to the remote NAS, in which case rsync the initial files would be better?

Many thanks!

Answer 1

It could be hard work trying to rename remote daily.0 directories to keep in sync with renaming done locally by rsnapshot. This might be needed to avoid an rsync of the entire snapshot directory from local to remote having to do a lot of work. It would be much simpler to have separate snapshots independently generated, locally and remotely. You will even gain some resilience if you separate them in time, so effectively doubling the snapshots.

You do not need to copy the local files to the remote before doing a remote snapshot, as rsnapshot on the remote can fetch the files over the network, i.e. you can locally backup files that are remote. rsync is optimised to reduce network bandwidth by only transferring the minimal amounts of data needed when a file changes, by calculating checksums of parts of the file locally and remotely.