Splitting a git-annex repository

I have a git annex repo for all my media that has grown to 57866 files and git operations are getting slow, especially on external spinning hard drives, so I decided to split it into separate repositories.

This is how I did it, with some help from #git-annex. Suppose the old big repo is at ~/oldrepo:

# Create a new repo for photos only
mkdir ~/photos
cd photos
git init
git annex init laptop

# Hardlink all the annexed data from the old repo
cp -rl ~/oldrepo/.git/annex/objects .git/annex/

# Regenerate the git annex metadata
git annex fsck --fast

# Also split the repo on the usb key
cd /media/usbkey
git clone ~/photos
cd photos
git annex init usbkey
cp -rl ../oldrepo/.git/annex/objects .git/annex/
git annex fsck --fast

# Connect the annexes as remotes of each other
git remote add laptop ~/photos
cd ~/photos
git remote add usbkey /media/usbkey

# Remove unneeded hard links
git annex unused
git annex dropunused --force 1-12345

# Sync
git annex sync

To make sure nothing is missing, I used git annex find --not --in=here to see if, for example, the usbkey that should have everything could be missing some thing.