User Quotas
First Commands:
mkdir -p /var/chroot/home/USER
chown example:example /var/chroot/home/USER
chmod 700 /var/chroot/home/USER
Edit /etc/ssh/sshd_config:
Match user USER
ChrootDirectory /var/chroot
Set quota:
sudo setquota -u USER 1000M 1100M 0 0 /