GIT & Symbolic Links

GIT & Symbolic Links

[Sassy Natan]

Hi Group,

I'm consider myself as a new baby when it come to GiT.
But I have just migrate my users from SVN to GIT and I have some
questions in mind I want to share with you.

Is it possible to do the following:

Say I have a really big GiT repo (something around 1GB) name DEV.
In the SVN days, each of my developers (100 Users) had to clone a
local copy of the DEV Repo in his home folder, so total of 100GB was
used in my shared storage (NFS Drive) where something around 85% was
actually just a copy of the same files.

When I used the De-Duplication function (Under ZFS File System) I
could easy see how the volume is shrinking, but I more inserting in
different kind of solution, now when it comes to GIT.

So for the example let's consider that user A clone the DEV GIT Repo
into his/her home folder (/home/A/DEV)
User B want to clone the same Repo. But now, I don't want user B to
clone the all tree and files, but instead to have a symbolic links to
the /home/A/DEV folder.
All files and directories in the /home/B/DEV will be a links to the /home/A/DEV.

Once user B actually want to change a file, ?somehow? the git brake
the link, and have a local copy of that specific file.
When the file is push back the link become back.

While trying to get some feedback in the IRC roon, some users point me
to git-annex and unionfs.
Both project seems to be cool, git-annex really have nice options, but
I don't see how this going to help me.

Regarding unionfs - well I'm still not sure.

Maybe someone can help here...

Thanks

Re: GIT & Symbolic Links

[Kevin]

As the IRC channel already concluded, git itself has no option to
'break' symbolic links on write, as git is not the only one editing
these files, but your editor does too.

This is why this is never going to work without the support of your
editor, or with something more low level, like file system support

On Mon, Mar 12, 2012 at 5:44 PM, Sassy Natan <sassyn@gmail.com> wrote:
> Hi Group,
>
> I'm consider myself as a new baby when it come to GiT.
> But I have just migrate my users from SVN to GIT and I have some
> questions in mind I want to share with you.
>
> Is it possible to do the following:
>
> Say I have a really big GiT repo (something around 1GB) name DEV.
> In the SVN days, each of my developers (100 Users) had to clone a
> local copy of the DEV Repo in his home folder, so total of 100GB was
> used in my shared storage (NFS Drive) where something around 85% was
> actually just a copy of the same files.
>
> When I used the De-Duplication function (Under ZFS File System) I
> could easy see how the volume is shrinking, but I more inserting in
> different kind of solution, now when it comes to GIT.
>
> So for the example let's consider that user A clone the DEV GIT Repo
> into his/her home folder (/home/A/DEV)
> User B want to clone the same Repo. But now, I don't want user B to
> clone the all tree and files, but instead to have a symbolic links to
> the /home/A/DEV folder.
> All files and directories in the /home/B/DEV will be a links to the /home/A/DEV.
>
> Once user B actually want to change a file, ?somehow? the git brake
> the link, and have a local copy of that specific file.
> When the file is push back the link become back.
>
> While trying to get some feedback in the IRC roon, some users point me
> to git-annex and unionfs.
> Both project seems to be cool, git-annex really have nice options, but
> I don't see how this going to help me.
>
> Regarding unionfs - well I'm still not sure.
>
> Maybe someone can help here...
>
> Thanks
> --
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Re: GIT & Symbolic Links

[Enrico Weigelt]

* Sassy Natan <sassyn@gmail.com> wrote:

Hi,

> So for the example let's consider that user A clone the DEV GIT Repo
> into his/her home folder (/home/A/DEV)
> User B want to clone the same Repo. But now, I don't want user B to
> clone the all tree and files, but instead to have a symbolic links to
> the /home/A/DEV folder.
> All files and directories in the /home/B/DEV will be a links to the /home/A/DEV.

Symlinks wont fit here, as the userland sees them as links (and treats
them as such). What you're looking for is some solution that does the cow
stuff hidden from the normal userland. Perhaps via unionfs or something
fuse-based.

BUT: I'd first raise the question if your tree needs to be that big
at all. Perhaps it should be splitted into several smaller ones.
What actually does your tree make that big ?


cu
-- 
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 Enrico Weigelt, metux IT service -- http://www.metux.de/

 phone:  +49 36207 519931  email: weigelt@metux.de
 mobile: +49 151 27565287  icq:   210169427         skype: nekrad666
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 Embedded-Linux / Portierung / Opensource-QM / Verteilte Systeme
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Re: GIT & Symbolic Links

[Andrew Sayers]

Not really an answer to your question, but `git-relink` will
de-duplicate the contents of your .git directory using hardlinks.  Your
actual files will remain as big as ever, but the (potentially much
larger) git storage for older versions will take considerably less disk
space.

	- Andrew