I have tried packedGitWindowSize, packedGitLimit, windowMemory, packSizeLimit and other options, but it seems that cloning the whole history still need a lot of memory and Git will be killed by OOM. Finally, I find that I can clone the latest commit of all branches with 'git clone --depth=1 --no-single-branch'. Although my local repository doesn't have any history commits, I can still track remote updates. I hope my approach can help someone who want to have a lightweight repository. Thanks for everyone's help ! Thanks, Hao Lee.