There are a couple of different things you can do.
1. Enable 'log' as the directive in the subject of your allow-all contract. These stats can then be viewed from the GUI by going to Tenants>tenant name>Operational>Flows/packets. Additionally these can be viewed from the cli of the switch by using "show logging ip access-list internal packet-log permit". Caveat though...permit logging is only supported on EX series switches.
2. Enable netflow if you have 2.2 running.
3. Buy tetration :)
