nbdkit VS dattobd

This is correct, but doesn't quite explain why. It's because when you accept contributions from a variety of authors, without using a CLA, then your code base ends up with a patchwork of copyright, making relicensing practically impossible as you have to get buy-in from every author or else determine that author's contributions and remove/rewrite them.

GPL/LGPL are excellent licenses, but this patchwork of copyright can apply for any license you use. For a small project we wrote which was under BSD, we recently had to make a small (non-functional) change to the license, and we got buy-in from all the authors to do this which took quite a long time: https://gitlab.com/nbdkit/nbdkit/-/commit/952ffe0fc7685ea775...

That second link is wrong, should be: https://gitlab.com/nbdkit/nbdkit/-/commit/a956e2e75d6c88eeef...

I think an exception might be made for a plain "C-like" struct that doesn't initialize members or contain anything except basic types. In the specific example[0] the code is actually surrounded by extern "C" { ... } so I suppose that the compiler "knows" this is a plain C struct?

[0] https://gitlab.com/nbdkit/nbdkit/-/blob/cd761c9bf770b23f678f...

We relicensed[1] a project which had 10 contributors, and we got every single one of them to do an Acked-by (by email) which took some weeks. That was the advice from our lawyers. Can't imagine the impossible hassle of doing the same for something like Linux.

[1] https://gitlab.com/nbdkit/nbdkit/-/commit/952ffe0fc7685ea775...

https://github.com/datto/dattobd is still a thing, apparently. Needs its own kernel module, so have fun with that.

There's https://github.com/datto/dattobd Never used it though.

(Or if you're really crazy, and want image based incremental backups then this exists https://github.com/datto/dattobd).

The dattobd [1] block device driver fills this gap. It basically implements VSS like behavior on Linux. It is used in the Datto Linux backup agent in combination with the backup appliance [2], but it can be used stand alone as well (see readme).

Disclaimer: I'm a software engineer for Datto.

[1] https://github.com/datto/dattobd

It connects but fails to back up a remote Linux server. Then I read from somewhere saying it works only in LAN. I ends up using https://github.com/datto/dattobd and rsync.

In my last job I worked on writing backup agents in C++ for multiple platforms using userspace API's. There was a team that exclusively worked on the Linux driver that our agent used, the driver is open source too - https://github.com/datto/dattobd