sadly requesting help

Hello,

My name is Raymond Augé. I'm a senior developer on the Liferay Portal project.

We had a colo failure over the last day or so and lost the last 50-60 commits on our subversion repository (apparently, our backup strategy was not granular enough).

Luckily I use Git locally using the git-svn conduit.

I need to rewind my repository to an earlier revision and I'm hoping not to have to rebuild my local repo as the project is huge and takes me at least 16 hours to checkout using git-svn.

I tried using:

git svn reset --revision 49343

where 49343 is the last revision before the failure.

But I'm at git version 1.6.3.3 which doesn't support the "reset" operation.

I tried various incantations of

git reset --hard <hash>

where <hash> matched the subversion revision obtained

git svn find-rev 49343

But that didn't clear the svn indexes which still think it's at the much later revision.

Does anyone know if there is an alternate way to rewind the "svn" portion of my repo to "forget" about the revs since 49343 so that I can restart the fetch process and catch up with the new stream (the git side seems to be more than ok with it)?

Sincerely,

Raymond Augé Liferay Inc.

On Tue, Mar 30, 2010 at 6:43 PM, Raymond Auge <raymond.auge@liferay.com> wrote:

I don't know about this option, but if it sounds like it would work, why not just upgrade your git? It's very easy (easier than most programs) to compile it from source.

You probably need something like:

    git update-ref refs/remotes/git-svn <commitid>

Where "refs/remotes/git-svn" is the ref that git-svn is using (you can usually find this with "git branch -r" and then prepend refs/remotes/ to the name it gives you). And <commitid> is the commit you want to be the "most recent" one from svn.

You may or may not also need to delete your svn cache dir (.git/svn). This should be harmless since git-svn can regenerate it later by reading through your local commits.

MAKE SURE YOU BACKUP YOUR REPO BEFORE TRYING ANY OF THIS ADVICE.

Good luck,

Avery

Raymond> We had a colo failure over the last day or so and lost the last Raymond> 50-60 commits on our subversion repository (apparently, our Raymond> backup strategy was not granular enough).

Raymond> Luckily I use Git locally using the git-svn conduit.

Raymond> I need to rewind my repository to an earlier revision and I'm Raymond> hoping not to have to rebuild my local repo as the project is Raymond> huge and takes me at least 16 hours to checkout using git-svn.

I know this does not answer your question, but why not use this incident to switch to git, or at least to seriously investigate a possible future switch to git?

As you probably know, with git it would have been really easy to restore the full repository if at least one person does have a local copy of each branch (typically, the last person to have committed on a branch is likely to still have a full copy of the branch). And backups can be done simply by running "git fetch" from a secondary machine at regular intervals.

Success story: the company I worked for in 2008 had a similar incident a few months after we switched from svn to git. Not only were we able to restore a full repository copy, but also we were able to work in the meantime by setting one of the developers machine as the central repository, and development work was not disrupted for more than one hour (we had to educate some developers who were not familiar with setting remotes other than "origin" and pushing to them). We ran this degraded setting for a few days (degraded because we lost continuous testing and packaging capabilities that ran on the main server, and developers had to run the test themselves by issuing frequent "make check" commands), but it was certainly not considered a major failure.

In four words: git saved the day.

  Sam

Thank you Samuel,

We have plans to migrate to git in the near-ish future.

I'm doing my best to show it's merits to my colleagues.

I'm still a newbie, with only weeks of experience. But already it has saved many hours of my time and allowed me to work much more effectively and comfortably. I have at least 5-10 local branches that I trivially hop across during the course of a day. I would have never dared to do this with subversion. It was hard to innovate, and since innovation is my job, git saved my day!

Ray

On Wed, Mar 31, 2010 at 4:53 AM, Samuel Tardieu <sam@rfc1149.net> wrote:

Raymond Augé Senior Software Architect Liferay Inc. -- Liferay East Coast Symposium Jun 8-9, 2010 Reston, VA Register today! -- Follow us on Twitter: liferay