Re: how to make "full" copy of a repo

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

On Sat, Mar 28, 2015 at 7:52 PM, Torsten Bögershausen <tboegi@web.de> wrote:
> On 2015-03-28 03.56, Christoph Anton Mitterer wrote:
>> Hey.
>>
>> I was looking for an ideally simple way to make a "full" copy of a git
>> repo. Many howtos are floating around on this on the web, with also lots
>> of voodoo.
>>
>>
>> First, it shouldn't be just a clone, i.o.w.
>> - I want to have all refs (local/remote branches/tags) and of course all
>> objects from the source repo copied as is.
>> So it's local branches should become my local branches and not remote
>> branches as well - and so on.
>> Basically I want to be able to delete the source afterwards (and all
>> backups ;) ) and not having anything lost.
>>
>> - It shouldn't set the source repo as origin or it's branches as remote
>> tracking branches, as said it should be identical the source repo, just
>> "freshly copied" via the "Git aware transport mechanisms".
>>
>> - Whether GC or repacking happens, I don't care, as long as nothing that
>> is still reachable in the source repo wouldn't get lost (or get lost
>> once I run a GC in the copied repo).
>>
>> - Whether anything that other tools have added to .git (e.g. git-svn
>> stuff) get's lost, I don't care.
>>
>> - It should work for both, bare and non-bare repos, but it's okay when
>> it doesn't copy anything that is not committed or stashed.
>>
>>
>>
>> I'd have said that either:
>> $ git clone --mirror URl-to-source-repo copy
>> for the direction from "outside" the source to a copy,
>> or alternatively:
>> $ cd source-repo
>> $ git push --mirror URl-to-copy
>> for the direction from "within" the source to a copy with copy being an
>> empty bare or non-bare repo,
>> would do the job.
>>
>> But:
>>
>> a) but the git-clone(1) part for --mirror:
>>    >and sets up a refspec configuration such that all these refs are
>>    >overwritten by a git remote update in the target repository.
>>    kinda confuses me since I wanted to get independent of the source
>>    repo and this ssems to set up a remote to it?
>>
>> b) do I need --all --tags for the push as well?
>>
>> c) When following
>>    https://help.github.com/articles/duplicating-a-repository/
>>    it doesn't seem as if --mirror is what I want because they seem to
>>    advertise it rather as having the copy tracking the source repo.
>>    Of course I read about just using git-clone --bare, but that seems to
>>    not copy everything that --mirror does (remote-tracking branches,
>>    notes).
>>
>>    So I'm a bit confused...
> This instructions have 3 repos:
> the source, "old", the destination "new" and a temporary one.
> As you only push to "new", "new" should have no information about
> "old" or "temp".
>>
>>
>> 1) Is it working like I assumed above?
>> 2) Does that also copy things like git-config, hooks, etc.?
>> 3) Does it copy the configured remotes from the source?
>> 4) What else is not copied by that? I'd assume anything that is not
>>    tracked by git and the stash of the source?
>
> You didn't write if this is a bare repository,
> if it is on a local disc, if it is reachable by rsync ?
> Linux or Windows ?
>
> For a "full clone" (in the sense of having everything, bit for bit)
> I would probably use rsync. (After stopping all activities on the repo)

This warrants more emphasis. If you rsync a repository that's
"active", i.e. getting pushes you *will* get corrupt copies. E.g. you
can easily copy something out of the objects directory that's in the
middle of being written, or copy the "refs" namespace after you copy
"objects" and end up with an unreachable object.

There's unfortunately no good solution to this other than doing both
git --mirror backups and rsync backups (for hooks etc.) and combining
the two, or pushing a hook for the duration that bans all updates.