Limit/cap resources on jails

Hello, Im getting into jails
I want to move away some KVM vms, and transform it into jails. My goal is to optimize (even more with jails) all resources, specially storage.
Currently Im running 2 vms with FreeBSD, vm1 has PHP7.1 and MariaDB and vm2 has PHP5.6 with MySQL. (vm1 should have more vCPUs but PHP5.6 uses more storage.

How can I limit resources for the jails, like qty of vCPUs, RAM and storage?
About storage Ive read that I can use md. But would not be efficient, since it would not increase or decrease info.

Thanks in advance for the information