Re: [PATCH 5/6] Teach "fsck" not to follow subproject links

From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Apr 12, 2007, 19:17 UTC
Message-ID: <Pine.LNX.4.64.0704121203290.4061@woody.linux-foundation.org>
In-Reply-To: <56b7f5510704121132g3961060amb394978bb49093e6@mail.gmail.com>

On Thu, 12 Apr 2007, Dana How wrote:

> 
> These arguments all seem pretty convincing to me --
> maybe the problem is that I'm not a "*developer*" right now.
> Instead I'm part of a multi-developer *site*.

Yes.

The issues for hosting sites are very different from the issues of individual developers having their own git repositories, and I agree 100% that both alternates and shared object directories make tons of sense for hosting.

> Below I talk about a possible way we could use git
> without changing it (since I recognize this would be a minority usage
> pattern).

I hope it wouldn't even be a minority usage pattern. I am a firm believer that distributed SCM's and git in particular makes a lot more sense for source control hosting than CVS or SVN do. I'm really disappointed with things like sourceforge, and part of the problem is literally that a centralized SCM is really *fundamentally* wrong for a hosting entity.

Using a distributed SCM just makes _so_ much more sense for hosting projects, and I've actually very much wanted to try to make sure that git can help people who host things.

It's not my *own* primary use, but I think it's a very important usage pattern, even though it's very different froma "normal developer" private sandbox case.

So I think your case is really very interesting. I'd love to help figure out how to help you guys with git, but because it's not how I personally work, I can really just try to help when you actually hit a problem - you'll have to figure out what your usage patterns actually are on your own ;)

And btw, I think the shared object model really works very well, but I think it has to be paired with some stricter rules than people who use their own repos tend to have. For example, end-point developers have become very used to rebasing and generally rewriting history (or just resetting to an older state), and that's something that works find in a "local repository" setup, but it's also the kinds of patterns that can really screw you in a hosted and shared-object environment.

As to your two setups: I would suggest you go with the "hidden" shared version (ie people use the remote access pull/push to a server, and the *server* uses a shared object repository for multiple repositories), rather than having a user-visible globally shared object directory. Even with sticky bits and controlled group access etc, I think it's just safer to have that extra level of indirection.

(Partly because a globally visible shared object directory also implies that you'd use a networked filesystem, and I suspect a lot of developers would actually be a lot happier having their own development repositories on their own local disks, or at least some "group disk", rather than have one big and performance-critical network share. Even if you use some competent NetApp box and a modern network filesystem, it's just one less critical infrastructure piece that needs to be really beefy).

		Linus