Selfhosted

Borg Backup. It can work locally or over network. Takes snapshots of the files you give it. Performs deduplication, compression and optionally encryption. You can check the integrity of the backups and repair them. There's a very simple to use GUI for it called Pika Backup to get you started.

Punch cards. Is it the best no but no one is going to bother to steal my data. Encryption through inconvenience

that doesn't require I keep a full local copy of all the data

If you don't do that, the place that you call "backup" is the only place where it is stored - that is not a Backup. A backup is an additional place where it is stored, for the case when your primary storage gets destroyed.

I use Borg Backup to a Hetzner storage box but doing the same thing to a disk array would work fine. How much data are you talking about? What is the usage picture? Backup and archiving are really not the same thing.

Rsync is liiiiifffeee

I like restic, it'll do deduplication and compression, it can backup to s3 or ssh or locally.

Are we talking personal offsite backup, or a commercial cloud service?

For cloud backups I like BackBlaze but I’ve never tried to use it as a general cloud storage drive.

rsync and another hard drive

I use rclone, with encryption, to S3. I have close to 3TB of personal data backed up to S3 this way - photos, videos, paperless-ngx (files and database).

Only readable if you have the passwords configured on my singular backup host (a RasPi), or stored in Bitwarden.

Would this work? https://rclone.org/

Where will the target be? Online or local? Rsync is really easy to use and the target files are browse-able. I could be too dense but I find online buckets aren't easily browse-able. Even a homemade NAS might be a good choice and it's easily scalable.

Sounds like something like "git annex" is what you're looking for?

I use this to manage all my photos. It lets you add binaries and synchronize then to a backend server (can be local, can be s3, back blaze, etc).

You can then "drop" files and it ensures a remote exists first. And when you drop the file your still see a symlink of it locally (it's broken) so that you know it exists.

My workflow is to add my files, sync them to both a local server and b2, then I drop and fetch folders as i need (need disk space? "git annex drop 2022*", want to edit some photos? "git annex get 2022_10_01".

All of my machines back up to my home server’s RAID over WebDAV with Nephele.

Then every few days I’ll manually sync them to a server at my parents’ house with a single huge HDD using rsync. I do this manually so that if anything happens to my home server (like ransomware) it doesn’t mirror destroyed data.

Since the Nephele share is just WebDAV, I can mount it locally and move things into it that I don’t want local anymore.

I created Nephele, and I just finished writing an encryption plugin. I wrote it because I’m also going to write an S3 adapter. That way, you can store things in S3, but they’ll be encrypted, so Amazon can’t see them.

rsync, for sure. That's what I used when I had to migrate a 10TB datastore to a new machins.

So i understood you just want some local storage system with some fault tolerance.
ZFS will do that. Nothing fancy, just volumes as either blockdevice or ZFS filesystem.

If you want something more fancy, maybe even distributed, check out storage cluster systems with erasure coding, less storage wasted than with pure replication, though comes at reconstruction cost if something goes wrong.

MinIO comes to mind, tough i never used it.. my requirements seem to be so rare, these tools only get close :/
afaik you can add more disks and nodes more or less dynamically with it.

What platform?

Another user said it - what your asking for isn't a backup, it's just data transfer.

It sounds like you're looking for a storage backend that hosts all your data and can download data to the client side on the fly.

If your use case is Windows, Nextcloud Desktop may be what you looking for. I have a similar setup with the game clips folder. It detects changes and auto uploads then, while deleting less recently used data that's properly server side. This feature might be in Mac but I haven't tested it.

Backup wise, I capture an rsync of the nextcloud database and filesystem server-side and store it on a different chassis. That then gets backed up again to a USB drive I can grab and run.

Nextcloud also supports external storage, which the server directly connects to: https://docs.nextcloud.com/server/latest/admin_manual/configuration_files/external_storage_configuration_gui.html

Hetzner storage box, rsync and a bash script

sshfs

Not.

Syncthing can do send only. It's pretty configurable.

But I'd probably use a cloud storage like storj.io, and tools like duplicati.

You could run a WebDAV server, like Nextcloud.

On windows it supports thin sync (meaning that it keep a reference to the file instead of the whole file), on Linux not yet, as it is still in alpha (but you can just connect it as a remote disk and be done with it. That's how I do with mines).

If you don't want the whole Nextcloud, there are standalone cli WebDAV servers.

Save your files to a local s3 object storage mount, enable versioning for immutability and use erasure coding for fault tolerance. You can use Lustre or some other S3 software for the mount. S3 is great for single user file access. You can also replicate to any cloud based S3 for offsite.