We saw a lot of talk in the panel about which nodes have write authority within a shard, but what about write authority between separate shards? Are separate persistence databases maintained for separate shards or will the states of world items eventually be synchronized between shards even if they were left in different states (i.e., a door is left open on one shard and left closed on another - will one shard eventually write its state to the database, updating the state of the door on the other shard?)
TL;DREach shard is its own copy of the universe with its own database, so item states aren't shared between shards, apart from a global player inventory database and special features like outposts and minable resources that replicate slowly.
Generally speaking, each shard is its own unique copy of the universe, and any item within the shard will not share state with an item from a different shard as each shard has its own database. On the other hand, we do have a global database for player inventory data. This database is used to store any item in a player's inventory, and items can transfer between shards if they first get stowed from a shard into an inventory and then unstowed into another shard.
Some features, such as player outposts or minable resources, implement special code that will replicate a global state to all shards, so an outpost may exist in multiple shards in parallel and slowly (relative to the speed of real-time play) replicate its state between shards. This isn't an instant replication (a door opening/closing will not be replicated), however, a persistent state like a door being locked or unlocked may be replicated between shards.
It's similar for minable resources: While each shard has a unique version of a minable rock, the overall amount will be replicated between shards, so when players start to mine a certain area, the global resource map for this area will be modified and the number of minable rocks in that location will be affected on all shards.