[ceph-users] [RGW] what is log_meta and log_data config in a multisite config?

Hi Cephers, In a multisite config, with one zonegroup and 2 zones, when I look at `radiosgw-admin zonegroup get`, I see by defaut these two parameters : "log_meta": "false", "log_data": "true", Where can I find documentation on these, I can't find. I set log_meta to true, because, why not ? Is it a bad thing ?