Trying to use git-filter-branch to compress history by removing large, obsolete binary files

Hi,

I'm using git-cvsimport to import some CVS repos, which unfortunately included dozens of large regression test output files in their ancient history...some of which measure hundreds of megabytes in size. I'd like to prune them out of the git history (I don't have access to prune them out of the CVS history), but I'm running into problems.

The following set of instructions will duplicate my problem with a smaller repo; why is the local git repository bigger after running git-filter-branch rather than smaller as I'd expect? I'm probably missing something obvious, but I have no idea what it is.

The steps:

# Make a small repo mkdir test cd test git init echo hi > there git add there git commit -m 'Small repo'

# Add a random 10M binary file dd if=/dev/urandom of=testme.txt count=10 bs=1M git add testme.txt git commit -m 'Add big binary file'

# Remove the 10M binary file git rm testme.txt git commit -m 'Remove big binary file'

# Compress the repo, see how big the repo is git gc --aggressive --prune du -ks . # 10548K du -ks .git # 10532K

# Try to rewrite history to remove the binary file git-filter-branch --tree-filter 'rm -f testme.txt' HEAD git reset --hard

# Try to recompress and clean up, then check the new size git gc --aggressive --prune du -ks . # 10580K !?!?!? du -ks .git # 10564K

Thanks, Elijah