下記を設定後に再起動
~ » sudo mkdir -p /System/Volumes/Data/sample ~ » sudo chown -R $USER:admin /System/Volumes/Data/sample ~ » echo -e 'sample\tSystem/Volumes/Data/sample' | sudo tee -a /etc/synthetic.conf
区切りはタブの必要がある
~ » cat /etc/synthetic.conf
sample System/Volumes/Data/sample
Source
Transcribed from Qiita.