So in the lecture Sharding Architecture it says a database may have a primary shard - does it mean database or mongod ?
So imagine I have 5 databases sat in a mongod instance e.g.
Now I have 3 shards in my sharded cluster 1 - 3. Could it in principle be
movies = Primary Shard 1
applicationData = Primary Shard 2
weather = Primary Shard 3