Database Reference
In-Depth Information
Replication
Continuing from the previous two points, Cassandra has a pretty powerful replication
mechanism (we will see more details in the next chapter). Cassandra treats every node in
the same manner. Data need not be written on a specific server (master), and you need not
wait until the data is written to all the nodes that replicate this data (slaves). So, there is no
master or slave in Cassandra, and replication happens asynchronously. This means that the
client can be returned with success as a response as soon as the data is written on at least
one server. We will see how we can tweak these settings to ensure the number of servers
we want to have data written on before the client returns.
From this, we can derive that when there is no master or slave, we can write to any node
for any operation. Since we have the ability to choose how many nodes to read from or
write to, we can tweak it to achieve very low latency (read or write from one server).
