Problem

If you have big repo, you want to separate it into several small repos.

There are two approach you might google it, here is different

Subtree

git subtree split -P feature_a -b "branchA"

It will separate your code, but it will include whole git history. It will slow-down your CI/CD flow if your original repo history is very huge.

Filter-Branch

which rewrites the repo history picking up only those commits that actually affect the content of a specific subdirectory. (refer to refer 2)

git filter-branch --prune-empty --subdirectory-filter SUBDIR -- --all

Reference

• Splitting a subfolder out into a new repository
• Difference between git filter branch and git subtree?
• Using Git subtrees for repository separation