In the Day 6 post, we expanded the initial Mutant Monitoring Scylla Cluster from one to two datacenters. Now we must begin to learn more about how to work with our data in such a setup. In this post, you will learn more about the consistency level options available when using Scylla with multiple datacenters.
Now, at Division 3 we must prepare for disaster readiness by expanding our Scylla cluster across geographic regions in a multi-datacenter configuration. In this post, we will set up a new Scylla cluster in another datacenter and learn how to convert our existing keyspaces to be stored in both datacenters.
— When data is written to Scylla, one or more replicas may become unresponsive or unreachable. The reasons for that may range from a heavy load on a particular replica node, network congestion, hardware issues, etc. As a result, the write to a replica will fail, usually with the timeout error. To restore the consistency of the data across all replicas, a user will have to run a repair, which is a very expensive—and usually long—procedure.