help needed: Splitting a git repository after subversion migration

Hello together,

I've successfully imported a large subversion repository into git. The tree contains source code and binary data ("releases"), the resulting .git directory is about 11GB.

After the import I recreated the tags/branches by converting the refs to the subversion tags using a small shell script from the web:

for branch in `git branch -r`; do
     ...
     version=`basename $branch`
     git tag -s -f -m "$subject" "$version" "$branch^"
     git branch -d -r $branch
done

Ok, so far everything went really smooth. I wanted to split this repository into two repositories, one for the source code and one for the binary data. The current tree layout is like this:

sources/c++_xyz releases/large_binary_data ...

The original tree was imported from CVS to subversion and the layout of the trunk was once reorganized/moved later. Here's the command I used to split out the "source" tree:

git filter-branch --index-filter 'git rm --cached --ignore-unmatch -r -f CVSROOT Attic source/Attic develpkg/Attic source/packages/Attic releases update_pkg' -- --all

After that I ran these commands to reclaim the space:
- git clone --no-hardlinks filtered_tree final_output
- cd final_output
- git gc
- git prune
- git repack -a -d --depth=250 --window=250

Unfortunately the .git directory of the "source" tree is still 7.5GB big.

When I just imported the "trunk" from subversion without any tags and then ran "git filter-branch --subdirectory-filter source" + git gc, the .git directory was about 1.5GB afterwards.

How can I find out where those other 6GB go to? I already looked at the tags with gitk, there's no sign of the releases/* stuff left.

The "--all" switch for "git filter-branch" doesn't seem documented in git 1.6.0.4? I just learned about it from the example usage.

"git filter-branch" also had trouble converting the tags and suggested I should add "--tag-name-filter cat", which I did. Maybe that's something for the examples, too?

I also tried running "git filter-branch --tag-name-filter cat --subdirectory-filter source -- --all", but that commands aborts with these messages:

WARNING: 'refs/tags/v5-0-8' was rewritten into multiple commits:
ee180f6117597b60ee237e9da92047946dfdeec5
fd7824d1926ce9e4c89b685583eb9a9c2f2537af
WARNING: Ref 'refs/tags/v5-0-8' points to the first one now.
error: Ref refs/tags/v5-0-8 is at 4ea78238cfd6ee259c4e8bde7be4a90bc86295b0 
but expected 06c60261502acfb7b2bbe44c2e2ec371bea65827
fatal: Cannot lock the ref 'refs/tags/v5-0-8'.
Could not rewrite refs/tags/v5-0-8

Besides that git really rocks :-)

Thanks in advance, Thomas