[ceph-users] Multisite design details

Hello All, I am looking to understand some of the internal details on how multisite is architected. On the Ceph user list, I see mentions of metadata logs, bucket index shard logs etc. but there is just no documentation anywhere I could find on how multisite works using these. Could someone please point me in the right direction here? Apart from the code, is there any resource that could help me with understanding the multisite internals? --Girish