Reduce git repository size by deleting directories no longer tracked by git

Goal

The git repository has grown too large because of files that are no longer tracked. Let’s remove those directories from past commits.

Environment

• git v2.45.0

Solution

1. Remove the specified directory from every branch in the repository

# Let's delete targetDirectory
git filter-branch --force --index-filter \
  "git rm -r --cached --ignore-unmatch targetDirectory" \
  --prune-empty -- --all

What the flags mean

• –index-filter “git rm -r –cached –ignore-unmatch targetDirectory” : Remove the directory from Git’s index (the staging area)
• –prune-empty: Remove commits that become empty after the deletion
• – –all: Apply to all branches

Remove git operation history

Git keeps a reflog that records its operation history. We expire it to remove unnecessary records.

git reflog expire --expire=now --all

Force Garbage Collection

Use Git’s garbage collection to remove unused objects. Using the Aggressive option lets you optimize more thoroughly.

git gc --prune=now --aggressive

Re-pack (compress) git objects

Since we just rewrote a lot of history, let’s re-compress git.

git repack -Ad

What is object packing?

This is an answer from GPT.

Object packing (pack) is the process of consolidating these individual objects into a single compressed file (or several files). Specifically:

• Saving space: Managing one large file instead of many small files reduces the disk’s metadata usage, so storage space is used more efficiently.
• Improved speed: Finding the data you need in a single large file can be faster than reading countless small files from the file system.
• Delta compression: By recording only the differences (deltas) between objects with similar content, you can achieve even greater storage savings.

git push

Let’s push the changes to the remote repository. Since we just rewrote a lot of history, you must use --force when pushing.

git push origin --force --all
git push origin --force --tags

EOD

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