Re: Could OSTree be, in theory, used for backups?

[Colin Walters <walters verbum org>]

On Fri, Aug 17, 2018, at 5:42 PM, Ryan Gonzalez via ostree-list wrote:

> This is why I'm asking the actual OSTree list: could it work for something
> like [backups], or would it be a terrible idea?

I believe fairly strongly that while backups and versioning for operating system/app updates
have a *lot* of similarities, it's best to have different software for them.   

For example, backups you commonly want to be encrypted and private,
whereas OS/app snapshots you usually want unencrypted and public.

For OSTree, it's usually N clients pulling from 1 upstream.  But for backups,
you usually have 1 machine having N backups (the reverse).

OSTree is designed around read-only checkouts, but for backups
you obviously want your apps to be able to edit in place.

If someone wanted to make a backup system using some of the ideas
or code in OSTree, that's great.  I could imagine one that wrapped it.
But I'd be pretty opposed to having ostree out of the box try to cater
to this use case directly.

This is a pretty different opinion than that of e.g. casync
http://0pointer.net/blog/casync-a-tool-for-distributing-file-system-images.html
which tries to do both.

Personally, I think we have our hands full handling code updates,
and there are *plenty* of backup systems out there; many fewer things
in the ostree space.

Another factor here honestly is that backup systems demand an extreme
level of reliability and testing - they tend to only get stress tested "in anger",
and I don't want to be the person who introduced a bug that ate someone's
vacation pictures from 2002 they really loved...