Bug#1028467: ITP: borgbackup2 -- version 2.x of a deduplicating and compressing backup program

[Helmut Grohne <helmut@subdivi.de>]

Hi Jonathan,

Thanks for your review.

On Tue, Jan 17, 2023 at 02:12:10PM +0000, Jonathan Dowland wrote:
> I'm not sure that alternatives is appropriate, if the commands are not
> interchangeable. And they are not: if you have 1 & 2 installed on a
> host, and have used one to create some backups, trying to use the other
> could be disastrous, and mixing them up a very real possibility if
> either could concretely own "borg". IMHO, borg1 got that name and should
> keep it, and borg2 should exclusively use a different command name, even
> though that makes us significantly divergent from upstream.

I agree that alternatives are not 100% appropriate for this situation,
but I think that it is a good trade-off.

The chances or destroying your backups are fairly minimal. Practically,
things will mostly stop working due to unknown options and commands.

I think that before too long, people want to get rid of borg 1.x and
forget about it. Keeping the 2 suffix is just making it painful down the
road. As such, I want a way that allows us to drop it eventually.

>From my point of view, there are three relevant scenarios:

1. A borg server. Such a system wants both borg 1.x and borg 2.x
   available to allow users to transitions their repositories when
   they're ready. Users should be advised to set BORG_REMOTE_PATH to
   something other than "borg" in this case.

2. New users installing borg 2.x for the first time. We really want them
   not to experience the transition cost. They should be able to use
   borg as if there never was borg 1.x.

3. Users upgrading from borg 1.x. Here, we want to decouple the borg
   upgrade from the dist-upgrade. To do this, users will have to install
   borg 2.x (not necessarily concurrently), transfer their repositories
   and adapt a few command lines.

Only in scenario 1 where the suffix is unavoidable and also being used
by major borg providers such as rsync.net, borgbase or hetzner, we don't
want to deal with suffixes.

And with that I arrive at update-alternatives being the best available
compromise. Do more people disagree with this plan?

Helmut