A Coggle Diagram about 重点关注的features http://vitess.io/overview/#features
(In Vitess, a shard is a partition of a keyspace. In turn, the keyspace might be a partition of the whole database. For example, a database might have one keyspace for product data and another for user data. The shard contains a subset of records within its keyspace.
and A Vitess shard typically contains one MySQL master and many MySQL slaves.