Dejadup - Which, i think, may use the dupliciti backend. I’m not sure if it is the best out there, but it seems solid, stable, and works well for doing other things besides ‘backups.’ For example, when upgrading to a larger (or smaller-faster) hard disk, the backup and restore functions work well in leu of DD. Seems like @popey had a similar issue a while back with his daughter’s laptop, and something like this might well have fixed his issue.
Of course they did forget the most effective filesystem again, that one with built-in snapshots and backups. All the mentioned backup software are amateurs compared to ZFS. ZFS that only sends the changed physical records and if they are compressed, they are send compressed. I even backup from my 2019 Ubuntu 20.04 Ryzen Desktop (64-bits) to my 2003 FreeBSD 12.1 Pentium-4 Backup-server (32-bits)
Part of the backup are 600 GB of lz4 compressed vdi files (virtual machines) between 8 and 40 GB each. Note that often half the vdi files have been updated by their OS. The incremental backup takes less than an hour on a 200 Mbps Ethernet link!
I use the backup since June 2019. The bottleneck for the 200 Mbps transfer speed is the Pentium 4 CPU, that runs one physical thread at 95% CPU load for the network process,
I have a couple of high-capacity microSD cards that I periodically load up with any photos or documents I want to keep. It’s not a perfect solution but my backup demands are pretty minimal.
I’m a fan of ZFS as well, However sometimes being restricted to a single filesystem isn’t good for a backups. ZFS snapshots work pretty well for replication and sending to off site backup locations.
Good idea, I have a 64 GB microSD card in my phone and it has my photos and my music (LP/CD). There is a lot of free space left and I could include it in my weekly backup process for personal stuff based on rsync and a working KDE-connect browsing function in my Xubuntu VM. I would consider it as my off-site backup.
Concretely, what do you mean with higher cost of entry? You did not notice, that I used two different OSes; one 64-bits Linux based and one 32-bits Unix/BSD based?
ZFS snapshots and tools is what I would use to back up NASs. but ZFS only works in the nix world and works well when only one host to backup repo is involved. Requires a lot of thought to set it up.
Rsync sits in the middle. Good with only one host per repo. but can work on Win, Mac, and Nix. not as complex to set up
Restic works on Win, OSX, and Nix, and works well with multiple hosts to one repository. Pretty easy to set up.
Maybe you did not notice it, but Ubuntu offers, since 19.04 to install its desktop OS on ZFS. Since Ubuntu 16.04 you can use ZFS as data storage in the Ubuntu desktop. I use ZFS on desktop and laptop since 2018 first as data storage and since 2019 as boot FS.
zfs work well for all file sizes for desktops and servers
rsync is fine, if you work with relative small files. It is lousy, if you have many large, GB-sized files
I haven’t uses ZFS on items other than servers. Wouldnt surprise me that it works on a small scale as well as large.
Restic is a backup tool that performs the deduplication and encryption on the client side, and stores everything on the repositories as files. Doesn’t require any special software on the target.
Great thing about restic is because it uses an index to reference deduplicated blocks, multiple hosts can be backed up to the same repository and gain the benefit of being deduplicated in the repository. I use crontab to run an hourly backup and it only takes 2 mins for it to check 500 GB worth of files in my home dir on my desktop and send the delta.