What is the advantage if we use peer-to-peer replication and sharding together?

Answer:

Using peer-to-peer replication and sharding is a common strategy for column-family databases. In a scenario we might have tens or hundreds of nodes in a cluster with data sharded over them. A good starting point for peer-to-peer replication is to have a replication factor of 3, so each shard is present on three nodes. Should a node fail, then the shards on that node will be built on the other nodes .