A subset of a cluster in an Eon Mode database. Subclusters isolate workloads to a group of nodes, letting you separate tasks such as load and query.

Subclusters come in two types: 

  • Primary subclusters count when Vertica determines whether the database can continue to run safely. Your database shuts down if less than half the primary nodes in your database are up, or does not have a primary node as a subscriber. Primary subclusters are best used for data loading and DDE workloads.
  • Secondary subclusters do not count towards maintaining data integrity. You can shut them down without impacting the stability of the database. Secondary subclusters are best used for query workloads. They cannot commit transactions directly, so they are less efficient at performing data loads and DDE statements.