Initializing single-token architecture datacenters
Steps for deploying when you are not using virtual nodes (vnodes).
In most circumstances, each workload type, such as search, analytics, and transactional, should be organized into separate virtual datacenters. Workload segregation avoids contention for resources. However, workloads can be combined in SearchAnalytics nodes when there is not a large demand for analytics, as combining transactional (OLTP) and analytics (OLAP) workloads result in decreases performance. You can enable DSE Graph only on the nodes you want to query.
When you create a keyspace using CQL, Cassandra creates a virtual datacenter for a cluster, even a one-node cluster, automatically. You assign nodes that run the same type of workload to the same datacenter. The separate, virtual datacenters for different types of nodes segregate workloads that run DSE Search from those nodes that run other workload types.
In this scenario, a mixed workload cluster has only one datacenter for each type of workload. For example, if the cluster has 3 analytics nodes, 3 Cassandra nodes, and 2 DSE Search nodes, the cluster would have 3 datacenters, one for each type of workload. In contrast, a multiple data-center cluster has more than one datacenter for each type of workload.
Prerequisites
- A good understanding of how Cassandra works. Be sure to read at least Understanding the architecture, Data Replication, and Cassandra's rack feature.
- Make sure your environment is suitable for your use case and workload.
- Review Recommended production settings for Linux.
- Choose a name for the cluster.
- For a mixed-workload cluster, determine the purpose of each node.
- Determine the snitch and replication strategy. The GossipingPropertyFileSnitch and NetworkTopologyStrategy are recommended for production environments.
- The IP address of each node.
- Ensure that DataStax Enterprise is installed on each node.
- Determine which nodes are seed nodes. Do not make all
nodes seed nodes.
Seed nodes are not required for DSE Search datacenters. Read Internode communications (gossip).
- Review and make appropriate changes to other property files, such as cassandra-rackdc.properties.
- Set virtual nodes correctly for the type of datacenter. See Virtual nodes.
Procedure
These steps provide information about setting up a having one or more datacenters.
Results
Datacenter: Cassandra
=======================
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving
-- Address Load Tokens Owns Host ID Rack
UN 110.82.155.0 21.33 KB 256 33.3% a9fa31c7-f3c0-... RAC1
UN 110.82.155.1 21.33 KB 256 33.3% f5bb416c-db51-... RAC1
UN 110.82.155.2 21.33 KB 256 16.7% b836748f-c94f-... RAC1